How to prove that $\lim_{(x,y)\to (0,0)} \frac{xy^5}{x^4+y^6}=0$
Multivariable limit proof: $\lim\limits_{(x,y)\rightarrow (0,0)}\frac{\left|x\right|^a\left|y\right|^b}{\left|x\right|^c + \left|y\right|^d} = 0$