Question

limit of x to 4 of (2^(x)-16)/(x-4)
what derivative does it represent?
what is the number of a?

Answer 1

looks like the notation is for the derivative of the function at 'a'\[f'(a)=\lim_{x \rightarrow a}\frac{f(x)-f(a)}{x-a}\]which is backwards from how I am used to seeing it, but is still good I guess.
spelling it out like this should make the answers clear