# How do you find the slope of a tangent line using secant lines?

##### 1 Answer

Sep 20, 2014

The slope of a tangent line can be approximated by the slope of a secant line with one of the end point coincides with the point of tangency. So, if the slope of the secant line from a to a+h is

then we can better approximate the slope of the tangent line by the slope of secant line by making