Nech� $f(x,y) = \root 3 \of {y - \cos x^2}.$ Spo�t�te
$\displaystyle \frac{\partial^2 f}{\partial x \partial y}, \,
\frac{\partial^2 f}{\partial y \partial x}, \,
\frac{\partial f}{\partial x}, \, \frac{\partial f}{\partial y}$
v bod� $(0,1),$ pokud existuj�.
