Tangent line illustration

The GeoGebra worksheet below shows the dependence of the tangent line on the point of tangency. The point of tangency is (a,f(a)). Using the slider to change the value of a changes the point of tangency, and the tangent line changes as well.

Here are the commands to produce this worksheet:

f(x) = x^3-2x^2
L = Tangent[1,f]
a = 1
Right click a under free objects, Properties, Slider, min -2 max 6.
Right click a under free objects, Show Object.
L = Tangent[a,f]

Craig L. Zirbel, Created with GeoGebra