Answer
See the explanation below.
Work Step by Step
Clairaut's Theorem states: suppose a function is considered to be 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 and the functions $f_{xy},f_{yx}$ are both continuous on the domain, then the following is true:
$f_{xy}(a,b)=f_{yx}(a,b)$
