Geometry

# Pythagorean Identities

## Intro

Trigonometric ratios form many different useful and beautiful identities that can be used to simplify inconvenient problem statements into manageable expressions. The concepts that you'll see in this chapter make use of Pythagoras's famous statement about the sides of a right triangle to concoct a few of these identities. Use trigonometry, love trigonometry, be $\sin^2(\theta) + \cos^2(\theta)$ with trigonometry.

Note that, unless mentioned otherwise, the only values used in identities are those that obtain real numbers.

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