How do I graph the portion of the sphere in the first octant?

I'm trying to graph x^2+y^2+z^2 = 4 in the first octant. How do I go about doing this?

Answer 1

[Mark Sherstan]

[x y z] = sphere;
r = 2;
surf(x*r, y*r, z*r);

xlim([0 2.5])
ylim([0 2.5])
zlim([0 2.5])