Sphere formula

*To*: mathgroup at smc.vnet.net*Subject*: [mg109432] Sphere formula*From*: "S. B. Gray" <stevebg at ROADRUNNER.COM>*Date*: Tue, 27 Apr 2010 04:05:16 -0400 (EDT)*Reply-to*: stevebg at ROADRUNNER.COM

1. The center of a sphere through 4 points has a very nice determinant form. (http://mathworld.wolfram.com/Sphere.html) What I want is a nice formula for the center of a sphere through 3 points, where the center is in the plane of the three points. I have a formula but it's a horrible mess of hundreds of lines, even after FullSimplify. 2. (Unlikely) Is there a way to get Mathematica to put a long formula into a matrix/determinant form if there is a nice one? Any tips will be appreciated. Steve Gray