Thursday, November 04, 2010

Why (-1)(-1) = 1?

Why (-1)(-1) = 1?

Two methods shown.
1. Use of distributive law
2. Use of the Rule of Indices

Some discussions are given to illustrate the use of negative numbers.

Polygons

Sum of Interior Angles of A Polygons
There are 4 different proofs shown here. I am sure students will enjoy them.