MathGroup Archive: June 2009 [00366]

[Date Index] [Thread Index] [Author Index]

polynomial of 7th order, some structure

To: mathgroup at smc.vnet.net
Subject: [mg100729] polynomial of 7th order, some structure
From: Anatoly <anatoly.bourov at gmail.com>
Date: Thu, 11 Jun 2009 21:44:56 -0400 (EDT)

hi, I have an equation i have been trying to solve, but no amount of
Solve, Reduce or ToRadical seems to produce an answer.

x(1+x^2)^3 == a x^4 +b x^3 +...+e

I know that it has one or three real roots, depending on combinations
of coefficients, with only one root at x>0.  That is the one that I
want, the root that is > 0.
Does anyone have any ideas what I can do?

I can plot the Root[] results, and I can see that it is usually the
same one root from the list, for most coefficient combinations.

Any way i can get the formula without plugging in the values?

Prev by Date: Re: Creating Matrix from vectors

Next by Date: Solving simultaneous integral equation

Previous by thread: Re: Correction to "Fundamental Theorem of Calculus and Mathematica"

Next by thread: Re: polynomial of 7th order, some structure