<meta http-equiv="refresh" content="1; url=/nojavascript/"> Solutions to Exercises | CK-12 Foundation
You are reading an older version of this FlexBook® textbook: Engineering: An Introduction to Solving Engineering Problems with Matlab Go to the latest version.

# 7.3: Solutions to Exercises

Difficulty Level: At Grade Created by: CK-12

Solution to Exercise 1

'$a$ is not equal to $0$'

Solution to Exercise 2

'$a$ is positive'

Solution to Exercise 3

b * c


gives

a


value of $6$, and $5 < 6$, so this code will print 'Hello world'.

Solution to Exercise 4

The parentheses around the relational expression

a > 0


will not change its validity, so this code will print 'a is positive'.

Solution to Exercise 5

The parentheses in this expression change its meaning completely. First,

a < b


is evaluated, and since it is false for the given values of

a


and

b


,

it evaluates to zero. The zero is then multiplied by

c


,

giving

a


value of zero which is interpreted as false. So this code prints 'Goodbye world'.

Solution to Exercise 6

'$p1$ and $p2$ are not equal'

Solution to Exercise 7

This code will generate an error message, since

a = b


assigns the value of

b


to

a


.

To check if

a


and

b


are equal, use

a == b


.

Solution to Exercise 8

Any value that is not zero.

Solution to Exercise 9

Any value greater than or equal to $0$ and less than $7$.

Solution to Exercise 10

Any value less than $3$ or greater than $10$.

Solution to Exercise 11

Every value of

a


will print 'Hello world'.

Solution to Exercise 12

The following code will provide the desired behavior:

if n >= -0.01 && n <= 0.01

disp('a is very close to zero')

end


Solution to Exercise 13

if n >= 1 && n <= 4

CA = 16.00;

elseif n >= 5 && n <= 24

CA = 14.00;

elseif n >= 25 && n <= 99

CA = 12.70;

else

CA = 11.00;

end


Solution to Exercise 14

This code by BrieAnne Davis:

if n >= 1 && n <= 4; %if n=1 to 4, CA is $16.00  CA=16.00;  elseif n >= 5 && n <= 24; %if n=5 to 24, CA is$14.00

CA=14.00;

elseif n >= 25 && n <= 99; %if n=25 to 99, CA is $12.70  CA=12.70;  elseif n >= 100; %if n=100 or more, CA is$11.00

CA=11.00;

end %this ends the if statement for CA

if n >= 1 && n <= 9; %if n=1 to 9, CB is $24.64  CB=24.64;  elseif n >= 10 && n <= 49; %if n=10 to 49, CB is$24.32

CB=24.32;

elseif n >= 50 && n <= 99; %if n=50 to 99, CB is $24.07  CB=24.07;  elseif n >= 100; %if n=100 or more, CB is$23.33

CB=23.33;

end %this ends the if statement for CB

if n >= 1 && n <= 24; %if n=1 to 24, CC is $17.98  CC=17.98;  elseif n >= 25 && n <= 49; %if n=25 to 49, CC is$16.78

CC=16.78;

elseif n >= 50; %if n=50 or more, CC is $15.78  CC=15.78;  end %this ends the if statement for CC  if n >= 1 && n <= 9; %if n=1 to 9, CD is$12.50

CD=12.50;

elseif n >= 10 && n <= 99; %if n=10 to 99, CD is $10.42  CD=10.42;  elseif n >= 100; %if n=100 or more, CD is$9.62

CD=9.62;

end %this ends the if statement

CO=45.00;

Cunit = CO + CA + CB + CC + CD;


Solution to Exercise 15

This code was originally written by Bryson Hinton and then modified:

cunit = zeros(1,150);

c0 = 45;

for n=1:150

%compute price for part A

if n >= 1 && n <= 4

ca=16;

elseif n >= 5 && n <= 24

ca=14;

elseif n >= 25 && n <= 99

ca=12.7;

else

ca=11;

end

%compute price for part B

if n >= 1 && n <= 9

cb=24.64;

elseif n >= 10 && n <= 49

cb=24.32;

elseif n >= 50 && n <= 99

cb=24.07;

else

cb=23.33;

end

%compute price for part C

if n >= 1 && n <= 24

cc=17.98;

elseif n >= 25 && n <= 49

cc=16.78;

else

cc=15.78;

end

%compute price for part D

if n >= 1 && n <= 9

cd=12.50;

elseif n >= 10 && n <= 99

cd=10.42;

else

cd=9.62;

end

%sum cost for all parts

cunit(n)= c0 + ca + cb + cc + cd;

end

% Plot cost as a function of n

plot(1:150,cunit);

xlabel('n (units)');

ylabel('cost (dollars)');

title('Cost/unit as a function of number of units');


This code produces the plot in Figure 1

Cost as a function of number of units produced.

Feb 23, 2012

Sep 15, 2014