Find the partial derivative fyf_yfy of f(x,y)=sin(xy)f(x, y) = \sin(xy)f(x,y)=sin(xy).
xcos(xy)x \cos(xy)xcos(xy)
ycos(xy)y \cos(xy)ycos(xy)
cos(xy)\cos(xy)cos(xy)
−xcos(xy)-x \cos(xy)−xcos(xy)