# Math Help - Critical points of function #2

1. ## Critical points of function #2

Find all critical points of the function
$f(x,y):= x^4 - 5x^2 + 12x sin y - 12 sin y,
x \in \Re, y \in (0,2\pi)$

2. Well, what difficulty are you having? Do you know the definition of "critical point"? Can you find the partial derivatives of this function?