Re: coefficients of polynomial
- To: mathgroup at smc.vnet.net
- Subject: [mg107953] Re: coefficients of polynomial
- From: dh <dh at metrohm.com>
- Date: Thu, 4 Mar 2010 05:24:42 -0500 (EST)
- References: <hmlf1q$jsd$1@smc.vnet.net>
Hi, Reduce can do this. E.g.: Reduce[ForAll[{x, y}, a x^2 + b x y + c y^2 == d (x + y)^2 + e (x - y)^2 + f (x^2 - y^2)], {d, e, f}] Daniel On 03.03.2010 11:52, Jim Armstrong wrote: > Hi, > > I am trying to find the coefficients d,e,f of this simple equating: > > ax^2+bxy+cy^2=d(x+y)^2+e(x-y)^2+f(x^2-y^2) > > I mean I am waiting for this type of solution: > > d=(a-b+c)/2 > e=b/2 > f=(a-c)/2 > > so how can I get these constants? > > I searched it and tried to use Solve, Expand...but either they dont give it or they solve it in terms of all terms (a,b,c,x,y). > > Thanks a lot > -- Daniel Huber Metrohm Ltd. Oberdorfstr. 68 CH-9100 Herisau Tel. +41 71 353 8585, Fax +41 71 353 8907 E-Mail:<mailto:dh at metrohm.com> Internet:<http://www.metrohm.com>