Derivative of y=cos(xy)
To find the derivative of this function, you'll need implicit differentiation.
derivative of y is just y'
derivative of cos(xy) requires chain rule AND product rule. It's -sin(xy)*(y+xy')
After taking this derivative, you'll need to multiply the -sin(xy) through the brackets (distribute) and then collect terms that contain y' on the one side of the equation. Then factor, and isolate y' with division.