Re: Ellipse equation simplification on Mathematica:

*To*: mathgroup at smc.vnet.net*Subject*: [mg77044] Re: Ellipse equation simplification on Mathematica:*From*: Narasimham <mathma18 at hotmail.com>*Date*: Fri, 1 Jun 2007 02:47:26 -0400 (EDT)*References*: <f2emof$35h$1@smc.vnet.net><200705300929.FAA13381@smc.vnet.net>

---- > >>>>> On May 19, 1:54 pm, Andrzej Kozlowski <a... at mimuw.edu.pl> wrote: > >>>>>> On 18 May 2007, at 19:06, Narasimham wrote: ---- > (-y^2)*(a - d)^2 + (a^2 - 2*d*a - c*(c + 2*cp*d))*(a - d)^2 + > (-a^2 + 2*d*a + c^2 + (cp^2 - 1)*d^2 + 2*c*cp*d)*x^2 = 0 ---- For case of cp= -1,when the tube is rotated by ph = 180 deg and moved horizontally,the taut threads cross each other in bow-tie/butterfly mode.The locus is an ellipse as simplification gives effective a and c simple relations. aEff = (a-d) and cEff = (c-d). Narasimham