Answer
$y^2 \cos(xy)i + (\sin(xy) + xy\cos(xy))j$
Work Step by Step
Get the derivative of $f(x,y)$ with respect to $x$ which is:
$f_x(x,y) = y^2\sin(xy)$
Get the derivative of $f(x,y)$ with respect to $y$ which is:
$f_y(x,y) = \sin(xy) + xy\cos(xy)$
Gradient of $f(x, y)$ is:
$\nabla f(x, y) = f_x(x,y)i + f_y(x,y)j$
$= y^2 \cos(xy)i + (\sin(xy) + xy\cos(xy))j$
