## Calculus: Early Transcendentals 8th Edition

a) Suppose a function is written as $f(x,y)$ with two variables $x,y$ in a set of domain D of real numbers which is continuous at the point $(a,b)$ along any closed path which lies inside the domain when it follows the below condition: $\lim\limits_{(x,y) \to (a,b)}f(x,y)=f(a,b)$ b) This means that the graph for the function $f(x,y)$ will be a surface or solid undisturbed surface without any holes or breaks.