trouble with $f'$ I'm having a lot of trouble understanding the core concept of finding $f\,'(a)$ or any number in place of $a$. I do not understand what finding $f\,'$ means to begin with, or how to solve them. If somebody could give any information i would be appreciative. 

It's just the derivative.
f'(a) is the derivative of f(x) at x=a.
So for example if f(x)=$x^2$ then f'(x)=$2x$ and f'(a)=$2a$
