Question

Each of the following functions has a set on which it is continuous and that set has a boundary. Match the verbal description of this boundary with the function by putting the letter of the boundary to the left of the letter of the function.

1. f(x,y)=1/(4−x^2−y^2)
2. f(x,y,z)=xyz/(x^2+y^2−z)
3. f(x,y,z)=1/(x^2+y^2+z^2)
4. f(x,y,z)=z/(1−x^2−y^2)
5. f(x,y)=xlny

A. one point
B. a circular parabaloid
C. a circular cylinder
D. a straight line
E. a circle

Answer 1

E1

B2

A3

C4

D5