1. ## multivariable calc question

Describe the given set with a single equation or with a pair of equations:

The set of points in space that lie 2 units from the point (0,0,1) and, at the same time, 2 units from the point (0,0,-1).

I got the circle x^2 +y^2=3, z=0
is this correct?

2. I agree 100% !

It would be a circle in $R^2$ with radius $\sqrt{3}$

which is what u have.