1. The problem statement, all variables and given/known data Find the absolute minimum and maximum values of f on the set D. f(x,y)= e-x2-y2(x2+2y2); D is the disk x2+y2 <= 4 2. Relevant equations Second Derivatives test, partial derivatives 3. The attempt at a solution fx(x,y) = 0 = (e-x2-y2)(-2x) + (x2+2y2)(-2x e-x2-y2) fy(x,y) = 0 = (e-x2-y2)(4y) + (x2+2y2)(-2y e-x2-y2) fxy(x,y) = (e-x2-y2)+(-2x)(-2y e-x2-y2) + (x2+2y2)(-2x*-2y e-x2-y2) + (-2x e-x2-y2)(4y) fx and fy simplify to: fx (x,y) = 1+x2+2y2 = 0 fy (x,y) = -2y+x2+2y2 = 0 I'm stymied here because the equation I get for fx seems impossible to solve. Did I make a mistake differentiating?