Find dy/dx

Question

Find dy/dx in terms of x and y if cos²(5y)+sin²(5y)=y+15

 

dy/dx=

Answer 1

we have the equation:

cos2(5y)+sin2(5y)=y+15

we know that cos²(5y) + sin²(5y) = 1, replacing in the equation we obtain:

1=y+15

y= -14

dy/dx = 0