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Course: Class 11 Math (India) - Hindi > Unit 3
Lesson 4: Trigonometric identities: Sum and difference- Review of trig addition identities (Hindi)
- Using the cosine angle addition identity (Hindi)
- Using trig addition identities finding sides (Hindi)
- Using the trig angle addition identities
- Proof of the sine addition identity (Hindi)
- Proof of the cosine angle addition identity (Hindi)
- Using the cosine double angle identity (Hindi)
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Using the cosine double angle identity (Hindi)
Lets evaluates the cosine of twice an angle whose right triangle is given. To do this, we must use the cosine double-angle formula.