Main content

## Precalculus

### Course: Precalculus > Unit 2

Lesson 9: Angle addition identities- Trig angle addition identities
- Using the cosine angle addition identity
- Using the cosine double-angle identity
- Using the trig angle addition identities
- Proof of the sine angle addition identity
- Proof of the cosine angle addition identity
- Proof of the tangent angle sum and difference identities

© 2023 Khan AcademyTerms of usePrivacy PolicyCookie Notice

# Using the trig angle addition identities

CCSS.Math: HSF.TF.C.9

## Problem

Stuck?

Stuck?