\documentclass[a4paper,12pt]{article}
\usepackage{epsfig}
\begin{document}
\parindent=0pt

\begin{center}
\textbf{Partial Differentiation}

\textit{\textbf{Functions of more than one variable}}
\end{center}

\textbf{Question}

Sketch the graph of the function.

$$f(x,y) = 4-x^2-y^2, \ \ \ (x^2+y^2\le 4, \ x \ge 0, \ y \ge 0)$$


\textbf{Answer}

\begin{center}
\epsfig{file=PD-1A-4.eps, width=50mm}
\end{center}

\end{document}