Slope of Tangent Line

Plug in a function in the f(x) input bar. Plug in the equivalent f(x+h) function in the f(x+h) input bar.
Move the point (x+h,f(x+h)) to match up with the point (x,f(x)).
What do you notice about the slopes of the secant line and tangent line before and after you move the points?

Think about the limit as h approaches 0. What slope does this represent? What was the slope before the limit is taken?

Janel Warren, 2 December 2013, Created with GeoGebra