a) Dada a funcal f(x, y)=\frac{2 x^{2}}{x^{2}+2 y^{2}}, verifigue se existe o limite \lim _{(x, y) \rightarrow(0,0)} f(x, y). Justifique
b) A funcail f(x, y)=\left\{\begin{array}{cc}\frac{2 x^{2}}{x^{2}+2 y^{2}} & \text { se }(x, y) \neq(0,0) \\\\ 0 & \text { se }(x, y)=(0,0)\end{array}\right.
écontinua em (0,0) ?