Proving trigonometric identities, part II Section 5.2b

Let’s start with this… Prove the identity: Setting up a difference of squares Pythagorean Identity  Answer

General Strategies III 1. Use the algebraic identity to set up applications of the Pythagorean identities. 2. Always be mindful of the “target” expression, and favor manipulations that bring you closer to your goal. Sometimes it’s even helpful to work from both sides towards a common intermediate expression…

Working from Both Sides Prove the identity: Start on the LHS: Not clear how to get from here to the RHS… Instead, let’s bring the RHS to this expression!!!

Working from Both Sides Prove the identity: Simplifying the RHS: We can now combine both parts for a complete proof.

A Plethora of Practice Problems Prove the identity:

A Plethora of Practice Problems Prove the identity:

A Plethora of Practice Problems Prove the identity:

A Plethora of Practice Problems Prove the identity: