Uppgift 3 av datorlabben

\[f(x,y) = \frac{(1-x^2)(y^2-4)-x^2-y^2+5}{(x^2+y^2+1)^2}\]

\[f_x =\frac{2 x (-y^4 + x^2 y^2 + 2 y^2 - 3 x^2 + 1)}{( x^2 + y^2 + 1)^3}\]

\[f_y = \frac{2 y (-x^4+x^2 y^2-7 x^2-2)}{(x^2+y^2+1)^3}\]