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Quadric

• To: mathgroup at smc.vnet.net
• Subject: [mg13747] Quadric
• From: MAvalosJr at aol.com
• Date: Wed, 19 Aug 1998 01:38:35 -0400
• Sender: owner-wri-mathgroup at wolfram.com

Hi Everyone: 

The parametric equations for  polynomial,e.g.,4 x^2 + y^2 - 8 x + 4 y -8
gives me an ellipse which doesn't match the ImplicitPlot of the
original polynomial. (??)
My eigenvalues are (4,1) and the eigenvectors are (1,0) and (0,1). My
parametric equations are Sqrt[2] Cos[t] and 2 Sqrt[2] Sin[t]. With
equation for ellipse with a mixed term,e.g., 3 x^2 -4 x y + 2 y^2-4,
there is no problem. 
Thanks in advance for any suggestions

MAvalosjr at aol.com