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Sums and Differences of Functions

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More Trigonometric Identities

Sums and Differences of Functions

The following formulas relate the sum of trigonometric functions of different angles to products of multiple angle functions. These identities are also useful for simplifying expressions.

sin(α) + sin(β) = 2 sin

cos

cos(α) + cos(β) = 2 cos

cos

sin(α) - sin(β) = 2 cos

sin

cos(α) - cos(β) = - 2 sin

sin

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