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