r(u,v)=⟨u,v,13(16−2u+4v)⟩ para ∣u∣<∞ y ∣v∣<∞\bold{r}(u, v) = \lang u, v,\frac13(16 − 2u + 4v) \rang\;\;\text{para}\;\; |u| \lt \infin\;\;\text{y}\;\; |v| \lt \infinr(u,v)=⟨u,v,31(16−2u+4v)⟩para∣u∣<∞y∣v∣<∞