Simple worksheet to visually show how secant line between two points on a curve approaches tangent line in the limit as h approaches zero.
Target audience: early Calculus classes first exploring definition of the derivative.
By sliding the 'h' slider, you can make h approach zero and the secant line becomes the line tangent at point c.
By sliding the 'c' slider you can change the point of tangency.
You can also change the curve itself by double-clicking on the equation in the algebra window.