There are only two types of problems:

Both of these problems are solved using the formula

.

Both of these problems are solved using the formula

Click here to see an animation illustrating the fact that the tangent line is the limiting position of the secant lines.
A better animation with audio is at www.calculus-help.com. The author uses "delta-x" to represent what we are calling h. Also, don't worry about knowing the word "derivative" he uses.

Additional homework for this lesson, which requires Adobe Acrobat Reader to view, is here.