Students remember identities better if they see how they are derived. This activity enables students to see the basic Pythagorean trig identity graphically and develop the others analytically.
Before the Activity
Students must be familiar with the basic trig ratios of sinx/cosx = tanx and cosx/sinx = cotx. They also should be able to recognize the graph of a constant function y = 1.
During the Activity
Students work independently through this activity to discover all three of the Pythagorean Trig identities.