University Calculus: Early Transcendentals (3rd Edition)

$\mathrm{Domain:}\ \ (-\infty,\infty)$ $\mathrm{See\:the\:graph\:below.}$
We can take the square root only of positive numbers. Since the absolute value of $\ x\$ will always give positive numbers, the domain of the given function is $\ y=\sqrt{|x|}\$ is $\ (-\infty,\infty).$ The graph of the given function $\ y=\sqrt{|x|}\$ is similar to the graph of $\ y=\sqrt{x}\$ when $\ x\geq0\$, but reflects itself along the $\ \mathrm{y-axis}\$ when $\ x<0.$ See the graph below.