Answer
$$f'(a)=\lim_{h\to 0}\frac{f(a+h)-f(a)}{h}$$
$slope$, $(a, f(a))$
Work Step by Step
The derivative of a function $f$ at a number $a$ is:
$$f'(a)=\lim_{h\to 0}\frac{f(a+h)-f(a)}{h}$$
if the limit exists. The derivative $f'(a)$ is the $slope$ of the tangent line to the curve $y=f(x)$ at the point $(a, f(a))$
