Use a for loop to evaluate

use a for loop to evaluate the function y = {exp(x+1) if x<-1, 2+cos(pi*x) if -1<=x<5, 10*(x-5)+1 if x>=5}

     e^(x+1) if x<-1
y = {2+cos(pi*x) if -1<=x<5
     10(x-5)+1 if x>=5

I am having trouble correctly setting up the for loop to store the values because the final product of this, is to plot the function y(x).

[Robert]

I forgot the range for the loop which is -2 to 6 increasing by 1 each time. Sorry!

[Azzi Abdelmalek]

What have you done so far?

Answer 1

[Ahmed]

according to my little knowledge if you need to store this value for every loop in a Matrix where every inner for loop represent a row you can do this

if 
y=zeros(9)
x=input('x=')
for i1=-2:6
y(i1)=.....
end
then y will be an array whose values are stored in the above Zero Matrix

Does this help ?

[Image Analyst]

You cannot have zero or negative indexes, like -2 or -1 or 0. You can either add 3 to i1, or use a counter like I did in my Answer.

Answer 2

[Image Analyst]

Try something like this:

index = 1;
for x = -2 : 1 : 6
  if x < -1
    % Insert code/formula here
    y(index) = .........whatever.....
  else if x >= -1 && x < 5
    % Insert other code/formula here
  else
    % x >= 5
    % Insert code/formula here
  end
  index = index + 1;
end
% Plot it.
plot(x,y, 'bo-', 'LineWidth', 3, 'MarkerSize', 15);
title('Plot of y vs. x', 'FontSize', 25);

[Robert]

Thank you. I will ask if you could generically go where the y(index) first appears. Basically what would the "whatever" be? I'm still very new to Matlab

[Image Analyst]

You insert the appropriate formula from your question:

y = e^(x+1)          if x<-1
y = {2+cos(pi*x)     if -1<=x<5
y = 10(x-5)+1        if x>=5