Differential equations need help!!

Find the differential equation for which 4xy^4 – 4xy^4sin(x) = 1 is an implicit solution on the interval (0, π/2). Write your answer in the form dy/dx = f (x,y) where f (x, y) depends on both x and y.

I got:
dy/dx=y^5(1-sin(x)-x*cos(x))

And i don't know why it is wrong

just take differentials of the ' solution '

4 y^3 ( 4x - 4x sin x) dy + y^4 ( 4 - 4 sin x - 4x cos x ) dx = 0...solve for dy / dx

{ y (x cos x + sin x - 1 ) / [ 4x ( 1 - sin x ) ] }