## University Calculus: Early Transcendentals (3rd Edition)

a. Domain : The domain is set of all $(x,y)$ in the xy plane b. Range: $R: z\geq 0$ c. Level Curves: We have for $f(x,y)=0$: origin and for $f(x,y)=c$: ellipses with center (0,0) and major and minor axes along $x$ and $y$-axes. d. No Boundary points e. Both Closed and open. f. Unbounded