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# Sum and Difference Identities

## Sine, cosine, or tangent of two angles that are added or subtracted.

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## Pythagorean Identities

by Caitlin Polzin //at grade

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## Double Angle Formulas

by EPISD Precalculus Team //at grade

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## Sum and Difference Formulas

by EPISD Precalculus Team //at grade

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• Video

## Sum and Difference Identities

by Phani Rayapaneni //at grade

Using the Sum and Difference Identities, examples of evaluating trigonometric expressions that require the use of the sum and difference identities for sine, cosine, and tangent are shown.

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