Different Tactics for Verifying Identities

There are many tactics and methods for proving the trigonometric identities. We present some of the most common and often used ones. With each identity, you need to inspect it first and then decide which method to choose.


There can be more than one way to verify a trigonometric identity. Your method might be different from the one we use. This provides a chance to be creative and even establish your favorite tactics for proving. However, it’s best to be efficient and prove identities the quickest way.

For each method or tactic discussed in this chapter, we provide some rationale and ...

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