MATLAB: Won’t Matlab plot anything

plot

When I try to plot anything, nothing comes up. There are no errors, there's just nothing.

>> x=-10:.1:10;
>> y=sin(x);
>> plot(x,y);
No figure window pops up.

You may have previous plot open somewhere and Matlab is plotting it on the same figure. Check for open figures, you might find it.

Alternatively, Use "close all" at the beginning and try again.

close all
x=-10:.1:10;
y=sin(x);
plot(x,y);

The loop does not work because x is not a vector after the loop. You have used x as the index variable, which is a scalar. Change your loop to this:

x = 0:.1:10;
y = zeros(size(x));
for i=1:numel(x)
    y(i)= sin(x(i));
end

Now x is still a vector after the loop.

You need to use ./, like

y=sin(x).^2./x.^2

HTH