## Calculus: Early Transcendentals 8th Edition

Suppose a function is written as $f(x,y)$ with two variables $x,y$ in a set of domain D of real numbers that approaches the point $(a,b)$ along any closed path which lies inside the domain. To show that the limit for such a function does not exist, we will have to two different paths that approaches the point $(a,b)$ with different limits.