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Kerala State Board New Syllabus Plus Two Maths Chapter Wise Previous Questions and Answers Chapter 1 Relations and Functions.

Kerala Plus Two Maths Chapter Wise Previous Questions Chapter 1 Relations and Functions

Plus Two Maths Relations and Functions 3 Marks Important Questions

Question 1.
Consider the set A = {1, 2, 3, 4, 5}, and B = {1, 4, 9, 16, 25} and a function ƒ : A → B defined by f(1) = 1, f(2) = 4, f(3) = 9, f(4) = 16 and f(5) = 25
(i) Show that f is one-to-one
(ii) Show that f is onto.
(iii) Does ƒ^-1 exists? Explain (May – 2013)
Answer:
(i) ƒ = {(1,1), (2,4), (3,9), (4,16), (5,25)}
Every element in A is mapped to different elements in B. Therefore one-to-one.
(ii) R (ƒ) = {1, 4, 9, 16, 25} = B. Therefore onto.
(iii) Since f is one-to-one and onto function, ƒ^-1 exists.
ƒ^-1 = {(1,1), (4,2), (9,3), (16,4), (25,5)}

Question 2.
a) When a relation R on a set A is said to be reflexive
b) Show that ƒ : [-1, 1] → R given by \(f(x)=\frac{x}{x+2}\) is one-one (May – 2015)
Answer:

Question 3.
a) The function ƒ :N → N given by ƒ(x) = 2x
i) one-one and onto
ii) one-one and not onto
iii) not one-one and not onto
iv) onto but not one-one
b) Find goƒ(x), if ƒ(x) = 8x³ and g(x) = x^1/2
c) Let * be an operation such that a*b= LCM of a and b defined on the set A = {1,2,3,4,5}. Is * a binary operation? Justify your answer. (March-2016)
Answer:
a) ii) one-one and not onto
b) Answered in previous years questions No. 2(ii) (6 Mark question)
c) LCM of 2 and 3 is 6 ∉ A, therefore not a binary operation.

Plus Two Maths Relations and Functions 4 Marks Important Questions

Question 1.
(i) ƒ : {1,2,3,4} → {5} defined by ƒ = {(1,5), (2,5), (3,5), (4,5)} Does the function is invertible?
(ii)
(iii) Let A = Nx N, N-set of natural numbers and * 1be a binary operation on A defined by (a,b) * (c,d) = (ac—bd,ud +bc). Show that* is commutative on A. (March -2011)
Answer:
(i) Inverse does not exists because fis not one-one.

Hence cummutative.

Question 2.
Let N be the set of Natural numbers. Consider the function ƒ: N → N defined by ƒ(x) = x + l, x ∈ N
(i) Prove that f is not onto
(ii) \(If g(x)=\left\{\begin{array}{ll}x-1, & x>1 \\ 1, & x=1\end{array}\right. then find g o f\)
(iii) Check whether goƒ is an onto function. (May 2011)
Answer:

(iii) Since f is not onto goƒ is also not onto.

Question 3.
(i) Give a relation on a set A = {1,2,3,4} which is reflexive , symmetric and not transitive.
(ii) Show that ƒ : [-1,1] → R given by \(f(x)=\frac{x}{x+2}\) is one-one.
(iii) Let ‘*’ be a binary operation on Q⁺ defined by a*b = \(a * b=\frac{a b}{6}\) ’.Find the inverse of 9 with respect to ’ * ’. (March -2012)
Answer:
(i) Given A = {1,2,3,4}
R = {(1,1)(2,2),(3,3),(4,4),(1,2),(2,1),(1,3),(3,1)}

Question 4.
(i) *:R x R → Ris given by a * b = 3a2 – b
Find the value of 2 * 3. Is ‘*’ commutative? Justify your answer.
(ii) ƒ :R → R is defined by ƒ(x) = x² – 3x + 2 Find ƒoƒ (x) and ƒoƒ. (May 2012)
Answer:

Question 5.
(i) Consider ƒ : R → R given by ƒ(x) = 5x + 2
(a) Show that f is one-one.
(b) Is f invertible? Justify your answer.

(ii) Let * be a binary operation on N defined by a * b = HCF of a and b
(a) Is * commutative?
(b) Is * associative? (March-2013)
Answer:
(i) (a) Let x₁, x₂, ∈ R
ƒ(x₁) = ƒ(x₂) ⇒ 5x₁ + 2 = 5x₂ + 2
⇒ 5x₂ = 5x₂ ⇒ x₁ = x₂
Therefore fis one-one.

(b) Yes.
Let y e range of ƒ
⇒ ƒ(x) = y ⇒ 5x + 2 = y
\(\Rightarrow x=\frac{y-2}{5} \in R\)
Therefore corresponding to every y ∈ R there existsa real number \(\frac{y-2}{5}\) Therefore f is onto.
Hence bijective, so invertible.

(ii) (a) Yes.
a * b = HCF (a,b) = HCF (b,a) = b * a
Hence commutative.

(b) Yes.
a * (b * c) = a* HF(b,c) = HCF(a,b,c)
(a*b) * c =HCF(a,b) * c HCF(a,b,c)
a * (b * c) = (a * b) * c
Hence associative.

Question 6.
(a) Let f: R → R be given by ƒ (x) = \(\frac{2 x+1}{3}\) find ƒoƒ and show that f is invertible.
(b) Find the identity element of the binary operation * on N defined by a * b = ab². (May 2014)
Answer:

Therefore f is onto.
Hence f is bijective and invertible.

(b) let ‘e’ be the identity element, then

Since e is not unique, this operation has no identity element.

Question 7.
a) What is the minimum number of pairs to form a non-zero reflexive relation on a set of n elements?
b) On the set R of real numbers, S is a relation defined as S = {(x,y)/X∈R, y ∈ R, x + y = xy}. Find a ∈ R such that ‘a’ is never the first element of an ordered pair in S. Also find b ∈ R such that ‘b’ is never the second element of an ordered pair in S.
c) Consider the function \(f(x)=\frac{3 x+4}{x-2}, x \neq 2\) Find a function on a suitable domain such that goƒ(x) = x = ƒog(x). (March 2015)
Answer:

Question 8.
(i) If ƒ: R → R and g: R → R defined by ƒ(x) = x² and g(x) = x + 1, then goƒ (x) is
(a) (x + 1)²
(b) x³ + l
(c) x² + l
(d) x + l

(ii) Consider the function ƒ: N → N, given by ƒ(x) = x³. Show that the function ‘ƒ’ is injective but not surjective.
(iii) The given table shows an operation on A = {p,q}

*	p	P
P	P	P
p	P	p

(a) Is * a binary operation?
(b) * commutative? Give reason. (May 2016)
Answer:
(i) (C) x² + 1
(ii) ƒ : N → N , given by ƒ(x) = x³
for x,y ∈ N ⇒ ƒ(x) = ƒ(y)
x³ = y³ ⇒ x = y

There fore f is injective.
Now 2 ∈ N, but there does not exists any element x in domain N such that ƒ(x) = x³ = 2 their fore f is not surjective.

(iii) (a) Yes
(b) No, because p*q = q; q*p = p
⇒ p*q ≠ q*p

Question 9.
(i) Let R be a relation defined on A{1,2,3} by R = {(13),(3,1),(2,2)} is
(a) Reflexive
(b) Symmetric
(C) Transitive
(d) Reflexive but not transitive.
(ii) Find fog and gof if ƒ(x) = |x+1| and g(x) = 2x – 1
(iii) Let * be a binary operation defined on N x N by (a,b) * (c,d.) = (a + c, b + d)
Find the identity element for * if it exists. (March – 2017)
Answer:
(i) (b) Symmetric

(ii) ƒog(x) = |g(x) + 1| = |2x – 1 + 1| = |2x|
goƒ(x) = 2 ƒ(x) – 1 = 2 |x + 1| – 1

(iii) Let e =(e₁, e₂) be the identity element of the operation in ? N x N then, (a,b)*(e₁, e₂) = (a + e₁, b + e₂) ≠ (a,b) Since, e₁ ≠ 0, e₂ ≠ 0

Therefore identity element does not existš.

Question 10.
(i) If R = {(x,y) : x, y ∈ Z, x – y ∈ Z}, then the relation R is
(a) Reflexive but not transitive
(b) Reflexive but not symmetric
(C) Symmetric but not transitive
(d) An equivalence relation.

(ii) Let * be a binary operation on the set Q of rational numbers by a*b = 2a + b. Find 2 * (3 * 4) and (2 * 3) * 4.
(iii) Let ƒ : R → R, g : R → R be two one-one funçtions. Check whether gof is one-one or not. (May- 2017)
Answer:
(i) (d) An equivalance relation.
(ii) 2* (3 * 4) = 2 * 10 = 14
(2 * 3)* 4 = 7 * 4 = 18
(iii) ƒ : R → R, g : R → R
Let x₁, x₂, ∈ R
goƒ(x₁) = g(ƒ(x₁)) = g(ƒ(x₂)) = g(ƒ(x₂))
⇒ x₁ = x₂

Plus Two Maths Relations and Functions 6 Marks Important Questions

Question 1.
(i) (a) A function ƒ : X → Y is onto if range of ƒ = ………….
(b) Let ƒ : {1, 3, 4} {3, 4, 5} and
g: {3, 4, 5} → {6, 8, 10} be functions defined by
ƒ (1) = 3, ƒ (3) = 4, ƒ (4) = 5;
g (3) = 6, g(4) = 8, g(5) = 8 ,then (goƒ) (3) = …………..

(ii) Let Q be the set of Rational numbers and ‘*’ be the binary operation on Q defined by \(a * b=\frac{a b}{4}\) for all a,b in Q
(a) What is the identity element of ‘ * ’on Q?
(b) Find the inverse element of * ’ on Q.
(c) Show that a * (b * c) = (a * b) * c, ∀a,b,c ∈ Q.
Answer:

Question 2.
(i) Let R be the relation on the set N of natural numbers given by
R = {(a,b): a – b > 2, b>3}
Choose the correct answer
(a) (4, 1) ∈ R
(b) (5, 8) ∈ R
(c) (8, 7) ∈ R
(d) (10, 6) ∈ R

(ii) If ƒ(x) = 8x³ and g(x) = x^1/3, findg(ƒ(x)) and ƒ(g(x))
(iii) Let * be a binary operation on the set Q of rational numbers defined by a*b = \(\frac{a}{b}\). Check whether * is commutative and associative? (March – 2014, May – 2015, March – 2016)
Answre:

Question 3.
Let \(f(x)=\frac{x-1}{x-3}, x \neq 3\) and \(g(x)=\frac{x-3}{x-1}, x \neq 1\) be two functions defined on R.

(i) Find ƒog(x), x ≠ 0
(ii) Find ƒ^-1 (x) and g^-1 (x), x ≠ 1
(iii) Find (goƒ)^-1 (x) (May-2010)
Answer:

Kerala State Board New Syllabus Plus Two Computer Application Notes Chapter 11 Trends and Issues in ICT.

Kerala Plus Two Computer Application Notes Chapter 11 Trends and Issues in ICT

Mobile Computing
The drawbacks of Desk computers are, it is heavy and power consumption rate is high and it is not portable(not mobile).
The advancements in computing technology, lightweight and low power consumption have led to the developments of more computing power in handheld devices like laptops, tablets, smartphones, etc.

Nowadays instead of desktops, lightweight and low power consumption devices are used because they are cheap and common. Moreover people are able to connect to others through the internet even when they are in motion.

Mobile Communication
The term ‘mobile’ help people to change their lifestyles and become the backbone of society. Mobile communication networks do not require any physical connection.

Generations in mobile communication
The mobile phone was introduced in the year 1946. Early-stage it was expensive and limited services hence its growth was very slow. To solve this problem, cellular communication concept was developed in 1960’s at Bell Lab. 1990’s onwards cellular technology became a common standard in our country.
The various generations in mobile communication are
a) First Generation networks(1G):
It was developed around 1980, based on analog. system and only voice transmission were allowed.

b) Second Generation networks (2G):
This is the next-generation network that was allowed voice and data transmission. Picture message and MMS(Multimedia Messaging Service) was introduced. GSM and CDMA standards were introduced by 2G.

i) Global System for Mobile(GSM):
It is the most successful standard. It uses narrowband TDMA (Time Division Multiple Access), allows simultaneous calls on the same frequency range of 900 MHz to 1800 MHz. The network is identified using the SIM(Subscriber Identity Module).

GPRS (General Packet Radio Services): It is a packet-oriented mobile data service on the 2G on GSM. GPRS was originally standardized by European Telecommunications Standards

Institute (ETSI) GPRS usage is typically charged based on the volume of data transferred. Usage above the bundle cap is either charged per megabyte or disallowed.

EDGE (Enhanced Data rates for GSM Evolution): It is three times faster than GPRS. It is used for voice communication as well as an internet connection.

ii) Code Division Multiple Access (CDMA):
It is a channel access method used by various radio communication technologies. CDMA is an example of multiple access, which is where several transmitters can send information simultaneously over a single communication channel. This allows several users to share a band of frequencies To permit this to be achieved without undue interference between the users and provide better security.

c) Third Generation networks (3G):
It allows a high data transfer rate for mobile devices and offers high-speed wireless broadband services combining voice and data. To enjoy this service 3G enabled mobile towers and handsets required.

d) Fourth Generation networks (4G): It is also called Long Term Evolution(LTE) and also offers ultra-broadband Internet facility such as high quality streaming video. It also offers good quality image and videos than TV.

e) Fifth Generation networks (5G): This is the next-generation network and expected to come into practice in 2020. It is more faster and cost-effective than the other four generations. More connections can be provided and more energy efficient.

Mobile communication services

a) Short Message Service(SMS): It allows transferring short text messages containing up to 160 characters between mobile phones. The sent message reaches a Short Message Service Center(SMSC), that allows ‘store and forward’ systems. It uses the protocol SS7 (Signaling System No7). The first SMS message ‘Merry Christmas’ was sent on 03/12/1992 from a PC to a mobile phone on the Vodafone GSM network in the UK.

b) Multimedia Messaging Service (MMS): It allows sending Multi-Media(text, picture, audio, and video file) content using mobile phones. It is an extension of SMS.

c) Global Positioning System(GPS): It is a space-based satellite navigation system that provides location and time information in all weather conditions, anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. The system provides critical capabilities to military, civil, and commercial users around the world. It is maintained by the United States government and is freely accessible to anyone with a GPS receiver. GPS was created and realized by the U.S. Department of Defense (DoD) and was originally run with 24 satellites. It is used for vehicle navigation, aircraft navigation, ship navigation, oil exploration, Fishing, etc. GPS receivers are now integrated with mobile phones.

d) Smart Cards: A smart card is a plastic card with a computer chip or memory that stores and transacts data. A smart card (may be like your ATM card) reader used to store and transmit data. The advantages are it is secure, intelligent and convenient.
The smart card technology is used in SIM for GSM phones. A SIM card is used as identification proof.

Mobile operating system: It is an OS used in hand held devices such as smart phone, tablet, etc. It manages the hardware, multimedia functions, Internet connectivity,etc. Popular OSs are Android from Google, iOS from Apple, BlackBerry OS from BlackBerry and Windows Phone from Microsoft.

Android OS: It is a Linux-based OS for Touch screen devices such as smartphones and tablets.lt was developed by Android Inc. founded in Palo Alto, California in 2003 by Andy Rubin and his friends. In 2005, Google acquired this. A team led by Rubin devel¬oped a mobile device platform powered by the Linux Kernel. The interface of Android OS is based on touch inputs like swiping, tapping, pinching in, and out to manipulate on-screen objects. In 2007 onwards this OS is used in many mobile phones and tablets. An¬droid SDK(Software Development Kit) is available to create applications(apps) like Google Maps, FB, What’s App,etc. It is of open-source nature and many Apps are available for free download from the Android Play Store hence increase the popularity. Different Android Versions are shown below:

Version – Code name
4.4 – KitKat
4.1 – Jelly Bean
4.0.3 – Ice Cream Sandwich
3.1 – Honeycomb
2.3 – Gingerbread
2.2 – Froyo
2.0 – Eclair
1.6 – Donut
1.5 – Cupcake

ICT in business: Drastic developments in ICT have changed the shopping habits of people. Earlier people shops traditionally. But nowadays people buy products and services online. A study reveals that online shopping habits of people are increased. Aftersale service is also good, delivery of the products is prompt and safe. The status of the product can be tracked easily hence increase the confidence level of the online customers.

Social networks and big data analytics: Earlier before buying a product people may consult two or three shop keepers or local friends and take decisions. But nowadays before taking decisions, people search shopping sites, social network groups(Facebook, WhatsApp, Instagram, Twitter, etc), web portals, etc. for the best prices. Almost all online sites have product comparison menus. By this, we can compare the price, features, etc. Earlier a product is created and customers are forced to buy. But today customer is the King of the market, so products are created for the choices of the customers.

So companies gathering information about the customers from various sources such as social media like Internet forums, social blogs, Microblogs, etc. The volume of such data is very large and considered big data in business. With the help of an s/w analysis this big data and generate a report that contains all the information such as choices, taste, needs, status etc of a customer.

Business logistics: It is the management of the flow(transportation) of resources such as food, consumer goods, services, animals etc in a business between the point of origin(source) and the point of consumption (destination) in order to meet the needs of companies and customers. Business logistics consists of many more complexities. The effective use of hardware and software reduces the complexities faced in Business logistics.

For this the hardware used is RFID(Radio Frequency Identification) tag and the reader. It is like the bar code. The RFID tag contains all the details of a product and it consists of a combination of a transmitter and a receiver. The data stored in the RFID tag can be accessed by a special reader and to read the data no need for an RFID tag and reader in a line of site instead both are within a range.

This tag is used in Vehicles as a prepaid tag and makes the payments easier in Toll booths. Similarly, it is useful to take the Census of wild animals also.

Information Security: The most valuable to a company(An enterprise ora Bank, etc) is their data base hence it must be protected from accidental or unauthorised access by unauthorised persons

Intellectual Property Right: Some people spend lots of money, time body, and mental power to create some products such as a classical movie, album, artistic work, discoveries, invention, software, etc. These types of Intellectual properties must be protected from unauthorized access by law. This is called Intellectual Property right(IPR).
Paris convention held in 1883 protects Industrial Property
Berne Convention held in 1886 protects Literary and Artistic work.
World Intellectual Property Organisation(WIPO) in 1960, Guided by the United Nations(UN) ensures/protects the rights of creators or owners and rewarded for their creation.

A person or an organization can register their Intellectual property such as creations, trademarks, designs, etc.

Intellectual property is divided into two categories

1. Industrial Property
2. Copyright

1) Industrial property: It ensures the protection of industrial inventions, designs, Agricultural products etc from unauthorized copying or creation or use. In India, this is done by the Controller of Patents Designs and Trademarks.

Patents: A person or organization that invented a product or creation can be protected from unauthorized copying or creation without the permission of the creator by law. This right is called Patent. In India, the validity of the right is up to 20 years. After this anybody can use it freely.

Trademark: This is a unique, simple and memorable sign to promote a brand and hence increase the business and goodwill of a company. It must be registered. The period of registration is for 10 years and can be renewed. The registered trademark under Controller General of Patents Design and Trademarks cannot use or^opy by anybody else.

Industrial designs: A product or article is designed so beautifully to attract customers. This type of design is called industrial design. This is a prototype and used as a model for large scale production.

Geographical indications: Some products are well known by the place of its origin. Kozhikkodan Halwa, Marayoor Sharkkara (Jaggery), Thirupathi Ladoo, etc are examples.

B) Copyright: The trademark is ©, copyright is the property right that arises automatically when a person creates a new work on his own, and by Law, it prevents the others from the unauthorized or intentional copying of this without the permission of the creator for 60 years after the death of the author.

Infringement (Violation): Unauthorized copying or use of Intellectual property rights such as Patents, Copyrights, and Trademarks are called intellectual property Infringement(violation). It is a punishable offense.

Patent Infringement: It prevents others from unauthorized or intentional copying or use of Patent without the permission of the creator.

Piracy: It is the unauthorized copying, distribution, and use of a creation without the permission of the creator. It is against the copy right act and hence the person committed deserves the punishment.

Trademark Infringement: It prevents others from unauthorized or intentional copying or use of Trademark without the permission of the creator.

Copy right Infringement: It prevents others from unauthorized or intentional copying or use of Copy right without the permission of the creator.

Cyberspace: Earlier Traditional communication services such as postal service(Snail mail) are used for communication. It is a low speed and not reliable service. In order to increase the speed Telegram Services were used. Its speed was high but it has lot of limitations and expensive too. Later telephones were used for voice communication. Nowadays telephone systems and computer systems are integrated and create a virtual(un real) environment. This is called cyberspace. The result of this integration is that tremendous speed and it is very cheap. The various departments of Govt, are providing speed, reliable and convenient online service hence increase productivity. Online shopping, Online banking, Online debate, Online Auction etc. are the various services offered by the Internet.

Through this one can transfer funds from our account to another account, hence one can pay bills such as telephone, electricity, purchase tickets(Flight, Train, Cinema, etc). As much as CyberSpace helps us that much as it gives us troubles.

Cyber Crimes: Just like normal crimes (theft, trespassing private area, destroy, etc,) Cybercrimes (Virus, Trojan Horse, Phishing, Denial of Service, Pornography etc) also increased significantly. Due to cybercrime, the victims lose money, reputation,etc and some of them commit suicide.

A) Cybercrimes against individuals
i) Identity theft: The various information such as personal details(name, Date of Birth, Address, Phone number etc), Credit / Debit Card details(Cand number, PIN, Expiry Date, CW, etc), Bank details, etc. are the identity of a person. Stealing this information by acting as the authorized person without the permission of a person is called Identity theft. The misuse of this information is a punishable offence.

ii) Harassment: Commenting badly about a particular person’s gender, colour, race, religion, nationality, in Social Media is considered as harassment. This is done with the help of the Internet is called Cyberstalking (Nuisance). This is a kind of torturing and it may lead to spoiling friendship, career, self-image and confidence. Sometimes may lead to a big tragedy of a whole family or a group of persons.

iii) Impersonation and cheating: Fake accounts are created in Social media and act as the original one for the purpose of cheating or misleading others. Eg: Fake accounts in Social Medias (Facebook, Twitter, etc), fake SMS, fake emails etc.

iv) Violation of privacy: Trespassing into another person’s life and try to spoil life. It is a punishable offense. A hidden camera is used to capture the video or picture and blackmailing them.

v) Dissemination of obscene material: With the help of hidden camera capture unwanted video or picture. Distribute or publish these obscene clips on the Internet without the consent of the victims may mislead people specifically the younger ones.

B) Cybercrimes against property: Stealing credit card details, hacking passwords of social media accounts or mail account or Net banking, uploading the latest movies etc, are considered as cyber crimes against property.

i) Credit card fraud: Stealing the details such as credit card number, company name, expiry date, CVV number, password etc. and use these details to make payment for purchasing goods or transfer funds also.
ii) Intellectual property theft: The violation of Intellectual Property Right of Copyright, Trademark, Patent, etc. In the film industry crores of investment are needed to create a movie. Intellectual Property thieves upload the movies on the Releasing day itself. Hence the revenue from the theatres is less significant and undergoes huge loss. (Eg: Premam, Bahubali, etc)
Copying a person’s creation and present as a new creation is called plagiarism. This can be identified as some tools(programs) available in the Internet

iii) Internet time theft: This is deals with the misuse of WiFi Internet facilities. If it is not protected by a good password there is a chance of misuse of our devices (Modem/Router) to access the Internet without our consent by unauthorized persons. Hence our money and volume of data(Package) will lose and we may face the consequences if others make any crimes.

C) Cybercrimes against the government: The cyber crimes against Govt, websites is increased significantly. For example in 2015 the website of the Registration Department of Kerala is hacked and destroys data from 2012 onwards.

i) Cyber terrorism: It deals with attacks against very sensitive computer networks like computer-controlled atomic energy power plants, air traffic controls, Gas line controls, telecom, Metro rail controls, Satellites, etc.. This is a very serious matter and may lead to a huge loss (money and life of citizens). So Govt is very conscious and give tight security mechanism for their services.

ii) Website defacement: It means to spoil or hacking websites and posting bad comments about the Govt.

iii) Attacks against e-governance websites: Its main target is a Web server. Due to this attack, the Web server/ computer forced to restart and this results in refusal of service to the genuine users. If we want to access a website first you have to type the web site address in the URL and press the Enter key, the browser requests that page from the webserver. Dos attacks send a huge number of requests to the webserver until it collapses due to the load and stop functioning.

Cyberethics
Guidelines for using computers over the internet

• Emails may contain Viruses so do not open any unwanted emails
• Download files from reputed sources(sites)
• Avoid clicking on pop-up Advt.
• Most of the Viruses spread due to the use of USB drives so use cautiously.
• Use a firewall on your computer
• Use anti-virus and update regularly
• Use spam blocking software
• Take backups in regular time intervals
• Use strong passwords, i.e a mixture of characters (a-z & A-Z), numbers, and special characters.
• Do not use bad or rude language in social media and emails.
• Untick ‘Remember Me’ before login.

CyberLaws: It ensures the use of computers and the Internet by people safely and legally. It consists of rules and regulations like the Indian Penal Code(IPC) to stop crimes and for the smooth functions of Cyberworld. Two Acts are IT Act 2000 and IT Act Amended in 2008

Information Technology Act 2000(amended in 2008)
IT Act 2000 controls the use of Computer(client), Server, Computer Networks, data, and Information in Electronic format and provides the legal infrastructure for E-commerce, in India.

This is developed to promote the IT industry, control e-commerce also ensures the smooth functioning of E-Governance and it prevents cyber crimes.

The person who violates this will be prosecuted. In India, the IT bill introduced in the May 2000 Parliament Session and it is known as the Information Technology Act 2000. Some exclusions and inclusions are introduced in December 2008

Cyber Forensics: Critical evidence of a particular crime is available in electronic format with the help of computer forensics. It helps to identify the criminal with help of blood, skin, or hair samples collected from the crime site?: DNA, polygraph, fingerprints are other effective tools to identify the accused person is the criminal or not.

Info mania: Right information at the right time is considered the key to success. The information must be gathered, stored, managed, and processed well. Infomania is excessive desire(infatuation) for acquiring knowledge from various modem sources like the Internet, Email, Social media, Instant Message applications (WhatsApp), and Smart Phones. Due to this, the person may neglect daily routines such as family, friends, food, sleep, etc. hence they get tired. They give first preference to the Internet than others. They create their own Cyber World and no interaction with the surroundings and the family.

Kerala State Board New Syllabus Plus Two Computer Application Notes Chapter 10 Enterprise Resource Planning.

Kerala Plus Two Computer Application Notes Chapter 10 Enterprise Resource Planning

The goal(aim) of the management of an enterprise(Proprietor of a Company or a Venture or an organization) is to handle the resources in a good manner and .make good profit. The resources include the employees, customers, raw materials, finished goods machinery etc… Hence an enterprise handles large amount of data(DataBase) such as employee data, customer data, raw material purchase, sales data, financial data etc. The size of data to be handle is large and hence the complexity is also high. To solve this problem .organizations use ERP packages

Overview of an enterprise
Let us consider a production unit in an enterprise. The activities involved are planning, purchasing raw material, production, storing finished goods(warehouse), sales, finance etc. These activities are performed by different departments and theirduties are interlinked. Altogether the resources are classified into four M’s, That is Man, Material, Money and Machine.

Concepts of Enterprise Resource Planning
An enterprise(organization) is considered as a system(A system is an orderly grouping of interdependent components linked together to achieve an objective, according to a plan. Human body is an example for System). All the departments of an enterprise are connected to a centralized data base. ERP consists of single database and a collection of programs to handle the database hence handle the enterprise efficiently and hence enhance the productivity.

Functional units of ERP
Different modules are given below:
Financial Module: It is the core. This is used to generate financial report such as balance sheet, general ledger, trial balances, financial statements etc.

Manufacturing Module: It provides information for the production and capable to change the methods in the manufacturing sector.

Production planning Module: This module ensures the effective use of resources and helps the enterprise to enhance productivity hence increase profit.

HR (Human Resource) Module: This model ensures the effective use of Human resources and Human capital.

Inventory control Module: This model is useful to maintain the appropriate level of stock(includes raw material, work in progress and finished goods)

Purchasing Module: This module is useful to make available the required raw materials in good condition and in the right time and price.

Marketing Module: It is used for handle the orders of customers.

Sales and distribution Module: The existence of a company is based on the income from sales. This module will help to handle the sales enquiries, order placement ans scheduling, dispatching and invoicing.

Quality (Ql & QC) management module: The quality of a product or service is very much important to a company.This module helps to maintain the quality of the product. Quality planning, inspection and control are the main activities involved in this module.

Business Process Re-engineering (BPR)
In this world, tight competition is based on price, quality, wide variety of selection and quick service. To increase the business and hence increase the profit of a Business firm various activities are involved. IT and Re-engineering play major roles to increase productivity.

In general, BPR is a series of activities such as rethinking and redesign the business process to enhance the enterprise’s performance such as reducing the cost(expenses), improve the quality, prompt, and speed(time-bound) service.

BPR enhances the productivity and profit of an enterprise.

A business process consists of three elements

1. Input – Supply data for processing
2. Processing – Series of activities to convert the input into output
3. Outcome – After processing, we will get the result as output.

The connection between ERP and BPR
ERP and BPR will not make much change if they are stand-alone. To improve the efficiency of an enterprise integrate both ERP and BPR because they are the two sides of a coin. For better results conducting BPR before implementing ERP, will help an enterprise to avoid unnecessary modules from the software.

Implementation of ERP
Wonderful changes are shown if you select and implement the correct ERP. Right ERP implemented at the right time will enhance the productivity and profit of an enterprise.

The different phases of ERP implementation are given below
Pre-evaluation screening: Many ERP packages are available in the markets. At most care should be taken before implementing an ERP. Select a few from the available ERP packages.

Package selection: The selection of the right ERP to our enterprise is a laborious task and it needs huge investment. Various factors should be kept in mind before you purchase an ERP that should meet our complete needs.

Project planning: Good planning is essential to implement an ERP. From the beginning to the end activities are depicted in this phase.

Gap analysis: A cent percent(100%) problem-solving ERP is not available in the market. Most of them solve a maximum of 70% to 80% problems. The rest (30% to 20%) of the problems and their solutions are mentioned here.

Business Process Reengineering: In general BPR is the series of activities such as rethinking and redesign of the business process to enhance the enterprise’s performance such as reducing the cost(expense), improve the quality, prompt and speed(time-bound) service.
BPR enhances the productivity and profit of an enterprise

Installation and configuration: In this phase the new system are installing, before implementing the whole system a miniature of the actual system is going to be implemented as a test dose. Then check the reactions if it is good it is the time to install the whole system completely.

Implementation team training: In this phase the company trains its employees to implement and run the system.

Testing: This phase is very important. It determines whether the system produces proper result. Errors in design and logic are identified.

Going live: Here a change over is taken place to new system from old system. It is not an easy process without the support and service from the ERP vendors.

End-user training: This phase will start familiarising the users with the procedures to be used in the new system. It is very important.

Post-implementation: Once the system is implemented maintenance and review begin. In this phase repairing or correct previously ill-defined problems and upgrade or adjust the performance according to the company needs.

ERP solution providers / ERP packages
The selection of right ERP is a difficult task. Many ERP packages are available in the market. Most of them are too expensive and cannot afford by small enterprises. The reason behind the expensiveness is that the ERP companies investing huge amount of time, money and effort in the research and development of ERP packages.

Popular ERP packages are given below
Oracle
American based company famous in database(Oracle 9i-SQL) packages situated in Redwood shores, California.
ERP package is a solution for finance and accounting problems. Their other products are

1. Customer Relationship Management (CRM)
2. Supply Chain Management (SCM) Software

SAP
SAP stands for Systems, Applications and Products for data processing.
It is a German MNC in Walldorf and founded in 1972. Earlier they developed ERP packages for large MNC. But nowadays they developed for small scale industries also.

The other software products they developed are

1. Customer Relationship Management(CRM)
2. Supply Chain Management(SCM)
3. Product Life cycle Management(PLM)

Odoo
Formerly known as OpenERP.
It is an open-source code ERP. Unlike other companies, their source code is available and can be modified as and when the need arises.

Microsoft Dynamics

• American MNC in Redmond, Washington
• ERP for midsized companies.
• This ERP is more user friendly
• Another s/w is Customer Relationship Management (CRM)

Tally ERP
Indian company situated in Bangalore.
This ERP provides a total solution for accounting, inventory and Payroll.

Benefits and risks of ERP
ERP packages have a lot of advantages as well as many drawbacks also.

Benefits of ERP system

1. Improved resource utilization: Resources such as Men, Money, Material, and Machine are utilized maximum hence increase productivity and profit.

2. Better customer satisfaction: Without spending more money and time all the customer’s needs are considered well. Because the customer is the king of the market. Nowadays a customer can track the status of an order by using the docket number through the Internet.

3. Provides accurate information: Right information at the right time will help the company to plan and manage future cunningly. A company can increase or reduce production based upon the right information hence increase productivity and profit.

4. Decision-making capability: Right information at the right time will help the company to make good decisions.

5. Increased flexibility: A good ERP will help the company to adopt good things as well as avoid bad things rapidly. It denotes flexibility.

6. Information integrity: A good ERP integrates various departments into a single unit. Hence reduce the redundancy, inconsistency, etc.

Risks of ERP implementation

1. High cost: Very huge investment is required to purchase and configure an ERP. Moreover, it requires up gradation or replacement of hardware(Man, computer, or machine) is an additional investment. So small-scale enterprises cannot afford this.

2. Time consuming: The full-fledged implementation of the ERP package needs one or two years. That is highly time-consuming.

3. Requirement of additional trained staff: The existing staff may not capable to work with ERP. To overcome this give proper training to them otherwise appoint trained and experienced employees to cop up.

4. Operational and maintenance issues: The first major problem is that the resistance from the existing employees. To overcome this give awareness to the existing employees. The second problem is that the ERP package is a cyclic process-oriented package. It is a continuous process and should be maintained well otherwise the correct output will not available.

ERP and related technologies
It is an all in one system. It integrates various functions such as raw material purchase, production planning, marketing, financial etc, into a single application.

Product Life Cycle Management (PLM): It manages the entire life cycle of a product. PLM consists of programs to increase the quality and reduce the price by the efficient use of resources.

Customer Relationship Management (CRM): As we know the customer is the king of the market. The existence of a company mainly the customers. CRM consists of programs to enhance the customer’s relationship with the company.

Management Information System (MIS): Management is the decision and policymakers. Good management can make a good decision and that will help to do the business well. A good relationship between Management and employees is a key to success. MIS will collect relevant data from inside and outside of a company. Based on this information produce reports and take appropriate decisions.

Supply Chain Management (SCM): This is deals with moving raw materials from suppliers to the company as well as finished goods from the company to customers. The activities include are inventory(raw materials, work in progress, and finished goods) management, warehouse management, transportation management, etc.

Decision Support System (DSS): It is a computer-based system that takes inputs as business data and after processing it produces good decisions as output that will make the business easier.

Kerala State Board New Syllabus Plus Two Computer Application Notes Chapter 9 Structured Query Language.

Kerala Plus Two Computer Application Notes Chapter 9 Structured Query Language

SQL – Structured Query Language developed at IBM’s San Jose Research Lab.

The result of the compilation of DDL statements is a set of tables, which are stored in a special file called a data dictionary.

Creating a database in Mysql
CREATE DATABASE <database_name>;
Eg: mysql>CREATE DATABASE BVM;

Opening a database
USE command used to use a database
USE <database_name>;
Eg: mysql>USE BVM;

SHOW command is used to list entire database in our system.
mysql>SHOW DATABASES;

Data Types

1. Char – It is used to store fixed number of characters. It is declared as char(size).

2. Varchar – It is used to store characters but it uses only enough memory.

3. Dec or Decimal – It is used to store numbers with decimal point. It is declared as Dec (size, scale). We can store a total of size number of digits.

4. Int or Integer – It is used to store numbers with¬out decimal point. It is declared as int. It has no argument. Eg: age int.

5. Smallint – Used to store small integers.

6. Date – It is used to store date. The format is yyyy-mm-dd.
Eg: ‘1977-05-28’.

7. Time – It is used to store time. The format is

DDL commands (3 commands)

• Create table
• Avertable
• Drop table

DML commands (4 commands)

• Select
• Insert
• Delete
• Update

DCL (Data Control Language) commands

• Grant
• Revoke

Rules for naming tables and columns

• The name may contain alphabets(A-Z, a-z), digits(0-9), underscore(_) and dollar ($) symbol
• The name must contain at least one character.
• Special characters cannot be used except _ and $
• Cannot be a keyword
• The name must be unique.

Constraints are used to ensure database integrity.

• Not Null
• Unique
• Primary key
• Default
• Auto_increment

Order By – Used to sort rows either in ascending (asc) or descending (desc) order.

Aggregate functions

• Sum() – find the total of a column.
• Avg() – find the average of 3 column.
• Min() – find the smallest value of a column.
• Max() – find the largest value of the column.
• Count() – find the number of values in a column.

Group by clause is used to group the rows. Having clause is used with Group By to give conditions.

Kerala State Board New Syllabus Plus Two Computer Application Notes Chapter 8 Database Management System.

Kerala Plus Two Computer Application Notes Chapter 8 Database Management System

DBMS means Data Base Management System. It is a tool used to store a large volume of data, retrieve and modify the data as and when required. DBMS consists of data and programs.

Advantages of DBMS

1. Data Redundancy
2. Inconsistency can be avoided
3. Data can be shared
4. Standards can be enforced
5. Security restrictions can be applied
6. Integrity can be maintained
7. Efficient data access
8. Crash recovery

Structure of DBMS

1. Fields – Smallest unit of data. Eg: Name, age, sex, …
2. Record – Collection of related fields.
3. File – Collection of records

Components of DBMS

1. Databases – It is the main component.
2. Data Definition Language (DDL) – It is used to define the structure of a table.
3. Data Manipulation Language (DML) – It is used to add, retrieve, modify and delete records in a database.
4. Users – With the help of programs users interact with the DBMS.

Database Abstraction – Abstraction means hiding, it hides certain details of how data is stored and main-tained.

Levels of Database Abstraction:

1. Physical Level (Lowest Level) – It describes how the data is actually stored in the storage medium.
2. Logical Level (Next Higher Level) – It describes what data are stored in the database.
3. View Level (Highest level) – It is closest to the users. It is concerned with the way in which the individual users view the data.

Data Independence – It is the ability to modify the scheme definition in one level without affecting the scheme definition at the next higher level.

1. Physical Data Independence – It is the ability to modify the physical scheme without causing application programs to be rewritten.
2. Logical Data Independence – It is the ability to modify the logical scheme without causing application programs to be rewritten.

Users of Database

1. Database Administrator
2. Application Programmer
3. New users

Data models – It is a collection of tools for describing data, data relationship, data semantics and consistency problem. 3 models.

1. Hierarchical model
2. Network model
3. Relational model

RDBMS – Relational DataBase Management System. It consists of a collection of relations as database.

Relation means table.

Domain – A pool of possible values from which col-umn values are drawn. ‘

Tuple means rows.

Attributes means columns.

Cardinality – The number of rows.

Degree – The number of columns

View – A view is a virtual table derived from one or more base tables.

Key is used to identify or distinguish a tuple in a relation.

Candidate key – It is used to uniquely identify the row.

Primary key – It is a set of one or more attributes used to uniquely identify a row.

Alternate key – Acandidate key other than the primary key.

Foreign key – A single attribute ora set of attributes, which is a candidate key in another table is called foreign key.

Relational Algebra – It consists of a set of opera¬tions that takes one or two relations as input and produces a new relation as a result.

1. Select operation (σ)
2. Project Operation (π)
3. Cartesian Product
4. Union Operation (∪)
5. Intersection operation (∩)
6. Set difference operation (-)

Kerala State Board New Syllabus Plus Two Computer Application Notes Chapter 7 Web Hosting.

Kerala Plus Two Computer Application Notes Chapter 7 Web Hosting

Web hosting
Buying or renting storage space to store website in a web server and provide service(made available 24×7) to all the computers connected to the Internet. This is called web hosting. Such service providing companies are called web hosts. Programming languages used are PHP, ASP.NET, JSP.NET, etc.

Types of web hosting
Various types of web hosting services are available. We can choose the web hosting services according to our needs depends upon the storage space heeded for hosting, the number of visitors expected to visit, etc.
1) Shared Hosting
2) Dedicated Hosting
3) Virtual Private Server (VPS)

Buying hosting space
We designed a website of our school and we decide our school website to be made available to all over the world, we have to place the website files on a web server for that we have to purchase hosting space(memory space) in a web server.
Following factors to be considered
1) Buying sufficient amount of memory space for storing ourwebsite files
2) If the web pages contain programming contents supporting technology must be consider
3) Based upon the programs select Windows hosting or Linux hosting

Domain Name System(DNS) Registration
Millions of websites are available over Internet so that ourwebsite must be registered with a suitable name. Domain Name registration is used to identify a website over Internet. A domain name must be unique(i.e. no two website with same name is available). So you have to check the availability of domain name before you register it, for this www.whois.net website will help. If the domain name entered is available then we can register it by paying the Annual registration fees through online.

FTP (File Transfer Protocol) client software When a client requests a website by entering website address. Then FTP client software helps to establish a connection between client computer and remote server computer. Unauthorised access is denied by using username and password hence secure our website files forthat SSH(Secure Shell) FTP simply SFTP is used. Instead of http://, it uses ftp://.
By using FTP client s/w we can transfer(upload) the files from our computer to the web server by using the ‘drag and drop’ method. The popular FTP client software are FileZilla, CuteFTP, SmartFTP, etc.

Free hosting
The name implies it is free of cost service and the expense is meet by the advertisements. Some service providers allow limited facility such as limited storage space, do not allow multimedia(audio and video) files.
A paid service website’s address is as follows
eg: www.bvmhsskalparamba.com

Usually two types of free web hosting services as follows
1) as a directory service.
Service provider’s website address/ ourwebsite address
eg: www.facebook.com / bvm hss kalparambu
2) as a Subdomain
Our website address, service providers website address
eg: bvmhsskalparamba.facebook.com

Earlier web hosting services are expensive but nowadays it is cheaper hence reduced the need for free web hosting.
Example for free web hosting.

Content Management System(CMS)
Do you heard about Data Base Management System(DBMS). DBMS is a software(collection of programs) used to create, alter, modify, delete and retrieve records of a DataBase. Similarly, CMS is a collection of programs that is used to create, modify, update and publish website contents. CMS can be downloaded freely and is useful to design and manage attractive and interactive websites with the help of templates that are available in CMS. WordPress, Joomla, etc are examples of CMS.

Responsive web design
The home page is displayed differently according to the screen size of the browser window(different screen sized devices-mobile phone, palmtop, tablet, laptop, and desktop) we used. The website is designed dynamically(flexibly) that suit the screen size of a different device introduced by Ethan Marcotte. Before this, companies have to design different websites for different screen sized devices. By responsive web design, companies have to design only one website that suitably displayed according to the screen size of the devices. It is implemented by using a flexible grid layout, images, and media queries

Flexible grid layouts: It helps to set the size of the web page to fit the screen size of the device.

Flexible image and video: It helps to set the image or video dimension to fit the screen size of the device.

Media queries: There is an option(settings) to select the size of the web page to match our device, this can be done by using media queries inside the CSS file.

A well known Malayalam daily Malayala Manorama launched their responsive website.

Kerala State Board New Syllabus Plus Two Computer Application Notes Chapter 6 Client-Side Scripting Using Java Script.

Kerala Plus Two Computer Application Notes Chapter 6 Client-Side Scripting Using Java Script

JavaScript(Original name was Mocha) was developed by Brendan Eich for the Netscape Navigator browser later all the browsers support this.

Getting Started With Javascript

Scripts are small programs embedded in the HTML pages, to write scripts <SCRIPT> tag is used.

Two types of scripts
1. Client scripts – These are scripts executed . by the browser(client) hence reduces network traffic and workload on the server.
2. Server scripts – These are scripts executed by the server and the results as a webpage returned to the client browser.

The languages that are used to write scripts are known as scripting languages. Eg: VB Script, Javascript etc.

Javascript and VB Script are the two client-side scripting languages.

Java script developed by Brendan Eich for the Netscape browser) is a platform-independent scripting language. Means It does not require a particular browser. That is it runs on any browser hence it is mostly accepted scripting language. But VB Script(developed by Microsoft) is a platform-dependent scripting language. Means it requires a particular browser(MS Internet Explorer) to work which is why it is not a widely accepted scripting language.

Attribute makes the tags meaningful

Language attribute specifies the name of the scripting language used.

Example:
<SCRIPT Language=”JavaScript”>
</SCRIPT>

The identifiers are case sensitive (means Name and NAME both are treated as different)

CamelCase: An identifier does not use special characters such as space hence a single word is formed using multiple words. Such a naming method is called CamelCase(without space between words and all the words first character is in upper case letter). These are two types
1) UpperCamelCase : when the first character of each word is capitalised.
Eg. Date Of Birth, JoinTime, etc….
2) LowerCamelCase: when the first character of each word except the first word is capitalised.
Eg. dateOfBirth, joinTime, etc,…

To write anything on the screen the following function is used document.write(string);
eg. document.writefWelcome to BVM HSS, Kalparamba”);

Note: Like C++ each and every statement in javascript must be end with semicolon(;).

To create a web page using javascript

<HTML>
<HEAD><TITLE>JAVASCRIPT- WELCOME</
TITLE></HEAD>
<BODY>
<SCRIPT Language=”JavaScript”>
document.write(“welcome to my first javascript page”);
</SCRIPT>
</BODY>
</HTML>

Its output is as follows

Creating Functions in Javascript

Function: Group of instructions(codes) with a name, declared once can be executed any number of times. There are two types
1) built in and
2) user defined

To declare a function, the keyword function is used.

A function contains a function header and function body

Even though a function is defined within the body section, it will not be executed, if it is not called.
Syntax:

function <function name>()
{
Body of the function;
}
Eg: function print()
{
document.write(“Welcome to JS”);
}

Here function is the keyword.
print is the name of the user defined function
To execute(call) the above function namely print do as follows:
print();
Eg:
<HTML>
<HEAD><TITLE>JAVASCRIPT- functions</
TITLE></HEAD>
<SCRIPT Language=”JavaScript”>
function print()
{
document.write(“welcome to my first javascript page using print function”);
}
</SCRIPT>
<BODY>
<SCRIPT Language=”JavaScript”>
print();
</SCRIPT>
</BODY>
</HTML>

Data Types in Javascript

Unlike C++ it uses only three basic data types
1) Number: Any number(whole or fractional) with or without sign.
Eg: +1977, -38.0003, -100, 3.14157,etc
2) String: It is a combination of characters enclosed within double quotes.
Eg: “BVM”, “jobi_cg@rediffmail.com”, etc
3) Boolean: We can store either true or false.lt is case sensitive. That means can’t use TRUE OR FALSE

Variables in Javascript

For storing values you have to declare a variable, for that the keyword var is used. There is no need to specify the data type.
Syntax:
var<variable name1> [, <variable name2>, <variable name3>, etc…]
Here square bracket indicates optional.
Eg: var x, y, z;
x = 11;
y = “BVM”;
z = false;
Here x is of number type, y is of string and z is of Boolean type.
typeof(): this function is used to return the data type
undefined: It is a special data type to represent variables that are not defined using var.

Operators in Javascript
Operators are the symbols used to perform an operation

Arithmetic operators
It is a binary operator. It is used to perform addition(+), subtraction(-), division(/), multiplication(*), modulus (%-gives the remainder) , increment(++) and decrement(–) operations.
Eg. If x = 10 and y = 3 then

If x = 10 then
document.write(++x); -> It prints 10 + 1 = 11
If x = 10 then
document.write(x++); -> It prints 10 itself.
If x = 10 then
document.write(–x); It prints 10 – 1 = 9
If x = 10 then
document.write(x–); -> It prints 10 itself.

Assignment operators
If a = 10 and b = 3 then a = b.
This statement sets the value of a and b are the same, i.e. it sets a to 3.
It is also called shorthands
If X = 10 and Y = 3 then

Relational(Comparison) operators
It is used to perform a comparison or relational operation between two values and returns either true or false.
Eg:
If X = 10 and Y = 3 then

Logical operators
Here AND(&&), OR(||) are binary operators and NOT(!) is a unary operator. It is used to combine relational operations and it gives either true or false
If X = true and Y = false then

Both operands must be true to get a true value in the case of AND(&&) operation
If X = true and Y = false then

Either one of the operands must be true to get a true value in the case of OR(||) operation
If X = true and Y = false then

String addition operator(+)
This is also called a concatenation operator. It joins(concatenates) two strings and forms a string.
Eg:
var x, y, z;
x = “BVM HSS”;
y = “Kalparamba”;
z = x + y;

Here the variable z becomes “BVM HSS Kalparamba”.

Note: If both the operands are numbers then the addition operator(+) produces a number as a result otherwise it produces a string as a result.

Consider the following

Eg:
1) 8(number) + 3(number) = 11 (Result is a number)
2) 8 (number) + “3”( string) = “83” (Result is a string)
3) “8” (string) + 3 (number) = “83”(Result is a string)
4) “8” (string) + “3” (string) = “83” (Result is a string)

Control Structures in JavaScript
In general, the execution of the program is sequential, we can change the normal execution by using the control structures.

Simple if Syntax:

if(test expression)
{
statements;
}
First the test expression is evaluated,

if it is true then the statement block will be executed otherwise not.

if-else Syntax:

if(test expression)
{
statement block1;
}
else
{
statement block2;
}

First the test expression is evaluated, if it is true then the statement block1 will be executed otherwise statement block2 will be evaluated.

Switch
It is a multiple bratich statement. Its syntax is given below.

switch(expression)
{
case value1: statements;break;
case value2: statements;break;
case value3: statements;break;
case value4: statements;break;
case value5: statements;break;
..................................
default: statements;
}

First expression evaluated and selects the statements with matched case value.

for loop
The syntax of for loop isgiven below

For(initialisation; testing; updation)
{
Body of the for loop;
}

while loop
It is an entry controlled loop The syntax is given below

Loop variable initialised
while(expression)
{
Body of the loop;
Update loop variable;
}

Here the loop variable must be initialised outside the while loop. Then the expression is evaluated if it is true then only the body of the loop will be executed and the loop variable must be updated inside the body. The body of the loop will be executed until the expression becomes false.

Built-in Functions (methods)
1) alert(): This is used to display a message (dialogue box) on the screen.
eg: alert(“Welcome to JS”);
2) isNaN(): To check whether the given value is a number or not. It returns a Boolean value.
If the value is not a number(NaN) then this function returns a true value otherwise it returns a false value.
Eg.

1. isNaN(“BVM”); returns true
2. isNaN(8172); returns false
3. isNaN(“680121″); returns false
4. alert(isNaN(8172); displays a message box as false

3. toUpperCase(): This is used to convert the text to uppercase.
Eg: var x=”bvm”;
alert(x.toUpperCase());

4. toLowerCase(): This is used to convert the text to lowercase.
Eg: var x=”BVM”;
alert(x.toLowerCase());

5. charAt(): It returns the character at a particular position.
Syntax: variable.charAt(index);
The index of first character is 0 and the second is 1 and so on.
Eg.var x=”HIGHER SECONDARY”;
alert(x.charAt(4));
Eg 2.
var x=”HIGHER SECONDARY”;
alert(“The characters @ first position is “+x.charAt(O));

6. length property: It returns the number of characters in a string.
Syntax: variable.length;
Eg.
var x=”HIGHER SECONDARY”;
alert(“The number of characters is “+ x.length);
Output is as follows(note that space is a character)

Accessing Values in a Textbox Using JavaScript.

Name attribute of FORM, INPUT, etc is very important for accessing the values in a textbox.

Consider the following program to read a number and display it

<HTML>
<HEAD><TITLE>JAVASCRIPT- read a value from the console</TITLE>
<SCRIPT Language=”JavaScript”>
function print()
{
var num;
num=document.frmprint.txtprint. value;
document.write(“The number you entered is ” + num);
}
</SCRIPT>
</HEAD>
<BODY>
<FORM Name=”frmprint”>
<CENTER>
Enter a number
< IN PUT Type=”text” name=”txtprint”>
<INPUT Type=”button” value=”Show” onClick= “print()”>
</CENTER>
</FORM>
</BOD Y>
</HTML>

In the above code,
print() is the user-defined function.
onClick is an event(lt is a user action). The function print() is executed when the user clicks the show button. Here code is executed as a response to an event.
frmprintisthe name of the form.
txtprint is the name of the text.

Ways to Add Scripts to a Web Page.

Inside <BODY> section
Scripts can be placed inside the <BODY> section.

Inside <HEAD> section
Scripts can be placed inside the <HEAD> section.
This method is a widely accepted method

External (another) JavaScript file
We can write scripts in a file and save it as a separate file with the extension .js. The advantage is that this file can be used across multiple HTML files and can be enhance the speed of page loading.