Prove that: For all $\epsilon>0$ exist $\delta>0$ which depends on $\epsilon$, such that:
$\left| {\frac{{2{x^2}y - x{z^2}}}{{yz - {z^2}}}}-0 \right|<\epsilon$ ever that $0 < \sqrt {{x^2} + {y^2} + {z^2}} < \delta $
I find it very difficult to find $\delta$ in terms of $\epsilon$. Any suggestions to prove this?
$\mathop {\lim }\limits_{(x,y,z) \to (0,0,0)} \left( {\frac{{2{x^2}y - x{z^2}}}{{yz - {z^2}}}} \right)=0$
thanks.