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From: "Peter Webb" <webbfamily@DIESPAMDIEoptusnet.com.au>
Newsgroups: alt.math.recreational,japan.sci.math,sci.math
References: <Ns6dne_eNZ5zdYTWnZ2dnUVZ_oydnZ2d@earthlink.com>
In-Reply-To: <Ns6dne_eNZ5zdYTWnZ2dnUVZ_oydnZ2d@earthlink.com>
Subject: Re: Solution to a Pentic
Date: Sat, 5 Dec 2009 18:07:00 +1100
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"Jon" <jon8338@peoplepc.com> wrote in message 
news:Ns6dne_eNZ5zdYTWnZ2dnUVZ_oydnZ2d@earthlink.com...
> Solution to a pentic:
>
> http://jons-math.bravehost.com/penticsoln.html
>
> This shows the steps to derive the formula below.
>
> The root to ax^5+bx+c=0 is,
>
> x = { -c*({a^2+b^2}^(1/2)+a)/(b^2+a*{a^2+b^2}^(1/2)) }^(1/5)
>
> Using this formula, the roots to,
>
> x^5+x-34=0  x=1.888  should be 2
> 32x^5+4x-3=0 x=0.623 should be 1/2
> x^5+x-0.10001 x=0.5887 should be 1/10
>
>
>

So the formula must be wrong.

Don't believe everything you read on the internet.