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

a. Domain : The domain is the set of all $(x,y)$ in the xy -plane. b. Range: A set of all Real numbers c. Level Curves: We have for $f(x,y)=0 \rightarrow$ $y \pm x$ and for $f(x,y)=c\ne 0$ hyperbolas with center (0,0) and foci on the x-axis when $c\gt 0$ and on the y-axis when $c\lt0$ d. No boundary points e. Both closed and open. f. Unbounded