Step 1: 
Complete Quiz 1. 
Step 2: 
If successful move on to the next topic. 

If unsuccessful investigate the topic using the websites below. 
Step 3: 
Complete Quiz 2. 
Step 4: 
If successful move on to the next topic. 

If unsuccessful investigate the topic further using the websites below. 
Step 5: 
Complete Quiz 3. 
Step 6: 
If successful move on to the next topic. 

If unsuccessful investigate the Further Resources below. 
There are probably two distinct areas that need attention in
differentiation, understanding the concept of derivative functions
and the mechanics of differentiation. The
http://www.univie.ac.at/future.media/moe/galerie/
has quite a lot of interactive material but some theoretical
introduction would be worthwhile. The site
http://cow.math.temple.edu/
is a calculus on the web (cow) site. It must be navigated through
carefully. It has a series of interactive problems and the help
button explains the theory. To consider differentiation go to
Calculus Book 1 and then the derivative. Before attempting the
problems push the help button to get the theory. The section on
limits is probably more technical than you need but the sections on
differentiation of polynomials and using the product, chain and
quotient rules is very good. There are very few other sites that are
reliably available.
The calculus booklet from the Maths Learning Centre at
http://www.usyd.edu.au/stuserv/academic_support/maths_learning_centre/publications.shtml.
is a good source of explanations and exercises.
An introduction to the concept of slope as a derivative can be
found at
http://www.univie.ac.at/future.media/moe/galerie/geom1/geom1.html.
It looks at the relationship between slope and angles as well as
introducing the concept of dx and dy.
The next site at
http://www.univie.ac.at/future.media/moe/galerie/diff1/diff1.html
has 5 applets, the first looks at the definition of derivative and
shows the tangent to a curve as you move along the curve, stating the
slope as it goes, the next 3 are useful puzzles that investigate the
relationship between a function and its derivative. It also links to
http://www.univie.ac.at/future.media/moe/tests/diff1/ablerkennen.html
a larger derivative puzzle of the same form as the 3 previous
applets. The site finishes with an applet on 1^{st} and 2^{nd}
derivatives. It looks at a cubic polynomial and shows what happens to
the function, its 1^{st} derivative and 2^{nd}
derivative as you change the coefficients of the polynomial.
