Why do I get "Array indices must be positive integers or logical values"?

delta_x = 2/40;
x = [];
for i = 1:1:41
    x = x (i-1) * delta_x;
end

[Adam]

This is one of the most helpfully descriptive error messages you get in Matlab. It tells you exactly what the problem is!

Answer 1

[madhan ravi]

Yes because index has to be positive where your loop starts from 1 if you index x as i-1 it means it’s zero that’s why the error arises. An example:

delta_x = 2/40;
  x = [1:41];
  for i = 1:length(x)
      x(i) = x(i)*delta_x;
  end
  x

[madhan ravi]

is it what you are looking for?