Explore BrainMass

Trigonometric Identities : Proofs and Simplifying Trigonometric Expressions

Please explain how to work these problems in steps

1. Prove this identity: sin(x+y)/sin(x-y) = coty+cotx/coty-cotx

8. Simplify: 2sinxcos³x-2sin³xcosx

9. If cosx=-¼and Pi/2 < x < pi, then cos (pi/6 - x) = ?

10. Prove this identity: cos8x=cos²4x-sin²4x

Solution Summary

Trigonometric identities are proven and simplifying trigonometric expressions is investigated. The solution is detailed and well presented.