Question

If cos (90°-0)=0 then sin (A+B)=

Answer 1

Step-by-step explanation:

Sin(A+B)= sinA.cosB+cosA.sinB

Answer 2

Answer:

Cos2B

Given Cos(A+B) = 0

=> A+B = (2n+1)*(pi/2) as only for these values of theta cos(theta) will be zero

=> A = (2n+1)*(pi/2) - B

=> A-B = (2n+1)*(pi/2) - 2B

=> Sin(A-B) = Sin((2n+1)*pi/2 - 2B)

=> Sin(A-B) = Cos(2B) as Sin((2n+1)*pi/2 - theta) = Cos(theta)