# Math Insight

### Overview of: Derivative from limit definition

The derivative as the limit of the slope of a secant line, where the distance between the points of the secant line goes to zero. For the derivative to exist at a point, the secant slope most approach the same value as the second point approaches that point from the left and from the right. When the secant slope approaches the same value from both sides, we say that the limit defining the derivative exists, i.e., the function is differentiable at that point.

Total points: 3