[newbie] algsys: tried and failed to reduce system to a polynomial in one variable; give up.
Subject: [newbie] algsys: tried and failed to reduce system to a polynomial in one variable; give up.
From: Jaime Villate
Date: Thu, 21 Feb 2013 10:24:29 +0000
On 02/21/2013 09:51 AM, Hugo Coolens wrote:
> I'm trying to determine 3 partial derivatives and figure out for which
> values they become zero, unfortunately this leads to the error
> mentioned in the subject:
> p:tau11*tau22;
> sigma:tau11+tau12+tau22;
> A:sqrt(p^2+2*p*sigma)-p;
> hjmax(p,sigma,A):=sqrt((1+A/p)/((1-A/sigma^2)^2+A/p));
> subst([A=sqrt(p^2+2*p*sigma)-p,sigma=tau11+tau12+tau22,p=tau11*tau22],hjmax(
>
> A,sigma,p));
> eqs:[diff(%,tau11),diff(%,tau12),diff(%,tau22)];
> unk:[tau11,tau12,tau22];
> solve(eqs,unk);
>
> can anyone here help me further?
Hi,
you are trying to solve analytically 18th degree polynomials with 3
variables. I think your only choice will be to use numerical methods.
Regards,
Jaime