Question

sina -1/sin(90-a). sina +
1/sin(90-a)​

Answer 1

Answer:

sin a-1/ sin(90-a)

sin a+1/sin(90-a)

sin(90-a) can be written as cos a

therefore, sin a-1/cos a and sin a-1/cosa

Identity used here is (a+b)(a+b)

sin2a-1/cos2a (sin2a-1 can be written as cos2a)

therefore, cos2a/Cos2a = 1