This site give the formula for finding the slope of the tangent line to a polar graph. The page offers step by step explanations and worked examples.

This site from Visual Calculus at the University of Tennessee provides very helpful exercises in graphing calculus problems. Provides ten exercises.

This online tutorial site shows that the concavity of a function is related to the second derivative of the function by using an online graphing system. Inflection points are also briefly discussed.