Unit 6: Trigonometric Identities

§6.1 Reciprocal, Quotient, and Pythagorean Identities

§6.1 notes

§6.2 Sum, Difference and Double-Angle Identities

§6.2 notes

Proving the Sum and Difference Identities for 
Sine and Cosine

http://pages.pacificcoast.net/~cazelais/173/idns-proof.pdf

§6.3 Proving Identities

§6.3 notes

§6.4 Solving Trigonometric Equations Using Identities

§6.4 notes