trig-identity-relation-between-cosine-and-sine
Deriving relationships between sine and cosine functions.
Instructions.
In this demonstration, you may drag the point P around the unit circle.
Question 1
Write an expression for in terms of the , and an expression for in terms of the angle . Notice that since is a rectangle. What conclusions can you draw? Express the lengths of segments and in terms of angle and respectively. What do you notice?
Question 2
Express the and in terms of angle and respectively. What do you notice?
Question 3 - Pythagorean Identity
Use the figure in the applet to derive the identity .