Consider the Piecewise-Defined Function Defined By $f(x)=\left\{\begin{array}{ll}x^{2}-6 & \text { if } x \leq 1 \\ \sqrt{x} & \text { if } x>1\end{array}\right.$

Essay

Consider the piecewise-defined function defined by $f(x)=\left\{\begin{array}{ll}x^{2}-6 & \text { if } x \leq 1 \\ \sqrt{x} & \text { if } x>1\end{array}\right.$ .
(a) Graph $f$ by hand.
(b) Use a graphing calculator to obtain an accurate graph in the window $[-5,10]$ by $[-10,10]$ .