Question

If cos(a +B) = 0, then sin(a - b) = ?​

Answer 1

Answer:

cos ( a+b) =0

cis ( a+ b) =cos 90°

(since, cos 90°=0)

a+b = 90°

a= b-90°

sin (a-b)=sin(90°-2b)=cos2b

(since, cos (90°- theta)=sin theta)

So, the answer is cos 2b.

Hope it helps u!