Move the slider , which represents the independent variable increment.
When B tends to A along the function graph, line tends to line , the tangent in A to the curve.
The limit of the difference quotient, as approaches 0, is the slope of the tangent to the curve in A.
You can also move the point A along the function and explore how the slopes of and of the tangent change accordingly.

Applying the definition, calculate the derivatives of the following functions, in the given points: