Question

4sinycosy=1

Answer 1

Recall that sin(2x) = 2sinx cos(x).
So your equation can be written as

2sin(2x)=1

sin(2x) = 1/2.

2x = 30 + K*180
So

x= 15 + k*90

In order x to be between 0 and 360, we choose k=0,1,2,3

So x=15, 105, 195 and 225 degrees.