Question

matlab only

Question 5: a.) Write an m-file using conditional statements to evaluate the following function, assuming that the scalar variable x has a value. The function is for x <-1 - 3e y=2+cos(m) for-1 x<5 y 10-5)+1 for r 2 5 Use your file to evaluate y for x5, x-3, and x-15, and Use keyboard entry for values of x. b.) Use a for loop in the above file to plot the above function over the interval -2x <10. Properly label the plot

Answer 1

MATLAB Script (Run it as a script, not from command window):

close all
clear
clc

fprintf('y(x = -5) = %.8f\n', func(-5))
fprintf('y(x = 3) = %.8f\n', func(3))
fprintf('y(x = 15) = %.8f\n', func(15))

x = input('Enter a value for x: ');
fprintf('y(x = %f) = %.8f\n', x, func(x))

x = -2:0.01:10;
y = zeros(1, length(x));
for i = 1:length(x)
y(i) = func(x(i));
end
plot(x, y), xlabel('x'), ylabel('y')

function y = func(x)
if x < -1
y = 3*exp(x + 1);
else
if x < 5
y = 2 + cos(pi*x);
else
y = 10*(x - 5) + 1;
end
end
end

Output:

y(x = -5) = 0.05494692
y(x = 3) = 1.00000000
y(x = 15) = 101.00000000
Enter a value for x: 2.5
y(x = 2.500000) = 2.00000000

Note: You need to enter some value for x when prompted and then at the end you get the plot.

Plot:

60 50 40 30 20 10 -2 4 6 10