Derivation of Basic Trigonometric Identities

PROVING TRIGONOMETRIC IDENTITIES

Many identities are derived from the fundamental identities. In the following LESSONs we will learn how to prove that an equation is an identity, thus discovering new identities.

Hints for Proving Trigonometric Identities

1. Choose a side (LHS or RHS) and use known identities to transform it into the other side. Starting with the more complicated side is usually the best option.

2. When dealing with these proofs it is generally useful to rewrite the given functions in terms of sine and cosine.

LESSON 1