Thread View: sci.math.num-analysis
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Started by Jon
Thu, 05 Aug 2004 06:41
Sure Polynomial Roots
Author: Jon
Date: Thu, 05 Aug 2004 06:41
Date: Thu, 05 Aug 2004 06:41
32 lines
2180 bytes
2180 bytes
If r is the root to the nth degree polynomial
a[0]+a[1]t+a[2]t^2+...+a[n]t^n=0
Then r is the solution to,
*******************************************
a[0]*ln|r|=
n
-SUM(1/p)*a[p]*c^p
p=1
n
+SUM(1/p)*a[p]
p=1
infinity
-a[0]SUM(-1)^(k+1) * a[0]/(k*c^k)
k=n+1
where
c={(-1)^n * a[0]/a[n] }^(1/n)
*******************************************
This computes roots to a high degree of accuracy and precision.
For an explanation on how this was derived and examples for its use, see
my web site at,
http://mypeoplepc.com/members/jon8338/polynomial/
Jon Giffen
Re: Sure Polynomial Roots
Author: Peter Pan
Date: Thu, 05 Aug 2004 11:06
Date: Thu, 05 Aug 2004 11:06
40 lines
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Jon <jon8338@peoplepc.com> wrote in message news:<4111D4FB.8050608@peoplepc.com>...
> If r is the root to the nth degree polynomial
>
> a[0]+a[1]t+a[2]t^2+...+a[n]t^n=0
>
> Then r is the solution to,
> *******************************************
> a[0]*ln|r|=
>
> n
> -SUM(1/p)*a[p]*c^p
> p=1
>
> n
> +SUM(1/p)*a[p]
> p=1
>
> infinity
> -a[0]SUM(-1)^(k+1) * a[0]/(k*c^k)
> k=n+1
>
> where
> c={(-1)^n * a[0]/a[n] }^(1/n)
> *******************************************
>
> This computes roots to a high degree of accuracy and precision.
>
> For an explanation on how this was derived and examples for its use, see
> my web site at,
>
> http://mypeoplepc.com/members/jon8338/polynomial/
>
> Jon Giffen
JON, PLEASE (!!!) STOP THIS NONSENSE !!!!!
Your method will not even find the root of
x-1=0
Re: Sure Polynomial Roots
Author: un.gabacho.sans.pourrier
Date: Thu, 05 Aug 2004 11:11
Date: Thu, 05 Aug 2004 11:11
1 lines
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Please place a followup to english speaking newsgroups.
Re: Sure Polynomial Roots
Author: Brian Smith
Date: Thu, 05 Aug 2004 12:42
Date: Thu, 05 Aug 2004 12:42
42 lines
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Jon <jon8338@peoplepc.com> wrote in message news:<4111D4FB.8050608@peoplepc.com>...
I see that you are no longer claiming to have solved the general
polynomial equation, now its just a numeric formula. Why should I
even consider this method for approximating roots when Newton's
iteration only needs the first derivative and only a few iterations
are needed to get the three place precesion that your method provides
in the example. I see no need to calculate dozens of terms when it is
so much simpler to let Newton's iteration run for more cycles.
> If r is the root to the nth degree polynomial
>
> a[0]+a[1]t+a[2]t^2+...+a[n]t^n=0
>
> Then r is the solution to,
> *******************************************
> a[0]*ln|r|=
>
> n
> -SUM(1/p)*a[p]*c^p
> p=1
>
> n
> +SUM(1/p)*a[p]
> p=1
>
> infinity
> -a[0]SUM(-1)^(k+1) * a[0]/(k*c^k)
> k=n+1
>
> where
> c={(-1)^n * a[0]/a[n] }^(1/n)
> *******************************************
>
> This computes roots to a high degree of accuracy and precision.
>
> For an explanation on how this was derived and examples for its use, see
> my web site at,
>
> http://mypeoplepc.com/members/jon8338/polynomial/
>
> Jon Giffen
Re: Sure Polynomial Roots
Author: Peter Pan
Date: Fri, 06 Aug 2004 00:10
Date: Fri, 06 Aug 2004 00:10
37 lines
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brianscsmith@yahoo.com (Brian Smith) wrote
>
> I see that you are no longer claiming to have solved the general
> polynomial equation, now its just a numeric formula. Why should I
> even consider this method for approximating roots when Newton's
> iteration only needs the first derivative and only a few iterations
> are needed to get the three place precesion that your method provides
> in the example. I see no need to calculate dozens of terms when it is
> so much simpler to let Newton's iteration run for more cycles.
AND ...
Jon's method calculates the solution of x - 1 = 0 as 0.7 ...
(ridiculous)
AND ...
the examples he gives on his website are NOT correctly calculated
AND
where is the notorious 'high degree of accuracy and precision'
as I said before: PLAIN BULLSHIT !!!
Hint: Use Newton's method, refined by Householder:
(1/p)k
x_(n+1)=x_n + (k+1)*------------(x_n)
(1/p)(k+1)
[the 'k' and 'k+1' at the (1/p)'s intends to mean k-th resp. (k+1)-th
derivative]
to obtain an approximation of real roots at an order of k+2 (iff you
have an appropriate starting value)
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