Derivative
Definition
The instantaneous rate of change of a function with respect to its variable. Geometrically, it represents the slope of the tangent to the curve at a given point. Formula: f'(x) = lim(h→0) [f(x+h) − f(x)] / h.
Example
"If f(x) = x³, then f'(x) = 3x². At x = 2, the rate of change (slope of tangent) = 3(4) = 12."