Using a variable in a function before it is defined.

I'm trying to create variables defined as the operations they perform at the specific iteration in the for loop; however, I am unsure how to define them before the iteration (i) is used.

Answer 1

[Image Analyst]

Why do you think it should know what "i" is at that point in your code? You never said what i is, so it's undefined.

I think you want something like

fpbackward = y(2:end) - y(1:end-1)/h;

(but I don't think you even want that, but whatever...that's what you wrote). That will take the prior elements and divide them by the scalar h and subtract them from the latter elements.