Question

Quick question. If you have lets say A(x)= the integral of R(x) from 0 to x. What is the relationship between A(x) and R(x)? is R'(x)=A(x)? I can't remember.

Answer 1

I think you want the other way around.
A'(x) = d/dx of the integral from 0 to x of R(t) dt. And by the fundamental theorem of Calculus, it reduces to A'(x) = R(x).

Answer 2

Thanks. I knew it was something like that.

Answer 3

No problem. It is similar to calling integrals a positive operator and derivatives a negative operator. Your original equation is at 0 for A(x) and +1 (1st integral) for R(x). We can evenly subtract 1 from both. -1 (1st derivative) for A(x) and 0 for R(x).