numerical analysis 3 rd

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Programming with MatLab

In this exercise, you are provided with an example problem and a practice problem. Run the example

problem in MATLAB to see how it works then complete the practice problem.

1. What does a statement such as z = 10 signify?

Answer: A statement such as z = 10 creates a variable named z, stores the value 10 in it,

and saves it in a part of computer memory known as the workspace.

Example 1:

Evaluate:

x = 3

y = 4

x

2

y

3

/ (x-y)

2

MATLAB PROGRAM:

(x^2*y^3)/(x-y)^2

ans = 576

Practice 1:

Use MATLAB to evaluate the following expression:

x =2, y = -1

1)

푥

2

푦

3

(푥

‒

푦)

2

3)

2)

4

2푥

3

4

2푦

3

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Example 2:

MATLAB program:

% This m-file calculates the area of a circle

% and displays the result.

radius = 2.5;

area = pi * radius ^2;

string = [‘The area of the circle is ’ num2str(area)];

disp(string);

Practice 2:

Calculate the volume of a cylinder of length = 0.5 m if the radius = 0.1m using the equation:

Volume = area of the base * length

Display the area and the volume the same way you did for the problem to calculate area.

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Example 3: sin x

% sin_x.m: This m-file calculates and plots the

% function sin(x) for 0 <= x <= 6.

x = 0:0.1:6

y = sin(x);

plot(x,y);

Practice 3:

Use MATLAB to plot absolute value of sin(t) between -2pi and 2pi with an increment of pi/10.

Hint: abs() is the command for absolute value.

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Example 4:

Input commands

Use MATLAB to write a small program called

asking

to prompt a user for his/her name,

after the user enters the name, the program outputs “Your name is

(name the user

inputs)

”.

ask = input ('What is your name? \n', 's');

response = ['Your name is ', ask];

disp (response)

The output is

>> asking

What is your name?

Carl

Your name is Carl

Practice 4:

Use MATLAB to write a small program called

Mailing

to prompt a user for his/her name,

and address after the user enters the name and the address, the program outputs the name

and address with the exact format of a mailing address that you will place on top of an

envelope to mail at the post office.

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Practice Problem 5:

1. With MATLAB use the Bisection method to find

p

3

for f(x) = x

3

– 9.

Write down an interval that contains a solution. (Read the lesson on Bisection technique

before solving this problem).