This limit represents the derivative of some function $\displaystyle f$ at some number $\displaystyle a$. State this $\displaystyle a$ and $\displaystyle f$.

How would you go about doing this? I understand that

$\displaystyle

f'(a) = \lim_{x \to a} \frac{f(x) - f(a)}{x-a}

$

but, it doesn't seem to apply for this. any help is appreciated!