Use polar coordinates to find the limit$.($x$^2-$y$^2)/(($x$^2+$y$^2)^(1/2))$

$[$Hint: Let x $=$ r cos $$

and

y $=$ r sin $,$

and note that

$($x$,$ y$)(0,0)$ implies r $0.]$

$$lim$($x$,$ y$)(0,0)$

x$2$ y$2$

x$2+$ y$2$

$$