1. Proving Trigonometric Identities
1. Proofs consist of a sequence of expressions, each one easily seen as equivalent to its preceding expression. 2. Begin with the more complicated, and work towards the less complicated expression.

2. Proving Trigonometric Identities
3. If no other move suggests itself, convert the entire expression to one involving sine and cosine. 4. Combine fractions over a common denominator (LCDs).

3. Proving Trigonometric Identities
5. Use the identities to set up/force applications of the Pythagorean identities (DOTS/factoring). 6. Always be mindful of the “target” expression, and favor manipulations that bring you closer to that goal.

4. 7.4 HW Assignment Pg. 474 #s 20-54 evens, 58, 62, 64, 96, 98