Let f(x,y)=ysin(x)f(x,y) = y \sin(x)f(x,y)=ysin(x). Compute the mixed second-order partial derivative fyxf_{yx}fyx.
cos(x)\cos(x)cos(x)
−cos(x)-\cos(x)−cos(x)
ycos(x)y \cos(x)ycos(x)
−sin(x)-\sin(x)−sin(x)