I have to calculate these two limits, and have no idea where to start from. Your guidance for how should I start working with it can help me a lot.
1) $\lim\limits_{(x,y,z)\rightarrow (0,0,0)} (1+xyz)^{(x^2+y^2+z^2)^{-1}}$
2)$\lim\limits_{(x,y)\rightarrow (0,0)} \dfrac{4y^2+3xy^2+2x^2}{x^2+2y^2}$
Thanks in advance.