## University Calculus: Early Transcendentals (3rd Edition)

$2$
Consider $\lim\limits_{(x,y) \to (0,0)} \dfrac{(\sqrt x-\sqrt y)(\sqrt x+\sqrt y+2)}{\sqrt x-\sqrt y}=\lim\limits_{(x,y) \to (0,0)} (\sqrt x+\sqrt y+2)$ Thus, we get $0+0+2=2$