is a sphere centred at the origin with radius
I can find the ellipsoid, paraboloid, and hyperboloid standard equation but, all I can find out about the sphere is the volume. It doesn't even mention the equation on wikipedia: Sphere - Wikipedia, the free encyclopedia. Does anyone know the standard equation for it?
Whether you write the equation as or or you should include the information that the point (a, b, c) (or (h, k, j) or [itex](x_0, y_0, z_0) is the center of the circle and that r is the radius.
You say you found the equations for ellipsoid, paraboloid, and hyperboloid (of one or two sheets?). What convention did they use for the center?