How to deal with (i-1)th iteration

Hi

I am drafting a program that involves "for" loop in which there is a term with A(i-1) in an expression. In this case, for the first iteration, i-1 results to zero but there won't be any value stored for A(0). How to deal with such situation

Answer 1

[KSSV]

You need to start iteration with 2 ...or take iteration from 1 to n-1.