The Sum and Difference Identities
More Lessons for Trigonometry
A series of free Trigonometry Lessons.
Trigonometric Identities to Evaluate Expressions (Sum and Difference Identity)
How to use a sum identity to evaluate sin(75 degrees) and tan (π/12)
Sum and Difference Identities
The sum and difference identities for sine, cosine, and tangent, followed by a few examples.
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