4sin (x) - 4=0

solve for x

First let's isolate the sin (x) term

4sin (x) - 4 = 0

4sin (x) = 4

sin (x) = 1

Now use the unit circle and you'll see that the only solution in the interval [0,2pi) is x = pi/2

If you want to ignore the restriction and consider all solutions, then x = (pi/2) + 2pi*n where n is any integer