Lawrence Hall of Science
The Math Page: An Approach to Calculus: Rules for Derivatives
Here is a site that clearly and thoroughly explains many rules for derivatives and proves or derives them. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out...
Lawrence Hall of Science
The Math Page: Skill in Algebra: Skill in Algebra: Complex or Imaginary Numbers
Clearly and thoroughly explains complex numbers. Provides example problems and exercises for students, with solutions available.