Question

tell the answer of Q 15

Answer 1

we know that when z is real
z= z conjugate as y=0
so
3+2i sin ]x / 1-2i sin x= 3-2i sin x / 1+2i sin x

{3+2i sin] x(1+2i sin x)= {3-2i sin x](1-2i sin x)

3+ 6isin x+2i sin x -4 sin^2 x= 3-8isinx -4 sin^2 x

so 3+ 8i sin x= 3 - 8i sin x
so
sin x= - sin x
only possible when x=n*pi