Find the Hessian matrix HfH_fHf of f(x,y)=x2yf(x, y) = x^2 yf(x,y)=x2y.
(2y2x2x0)\begin{pmatrix} 2y & 2x \\ 2x & 0 \end{pmatrix}(2y2x2x0)
(2x2y2y0)\begin{pmatrix} 2x & 2y \\ 2y & 0 \end{pmatrix}(2x2y2y0)
(yxxy)\begin{pmatrix} y & x \\ x & y \end{pmatrix}(yxxy)
(2110)\begin{pmatrix} 2 & 1 \\ 1 & 0 \end{pmatrix}(2110)