Prove that

(i)

(ii)

(iii)

(iv)

If, where

, find the values of

(i) sin (x + y)

(ii) cos (x + y)

(iii) tan (x – y)

If , where , find the values of

(i) sin (x + y)

(ii) cos (x – y)

(iii) tan (x + y)

Prove that

(i)

(ii)

(iii)

Prove that

sin(150⁰ + x) + sin (150⁰ – x) = cos x