From: Shubha Vishwanath Karanth <shubhak_at_ambaresearch.com>

Date: Sat, 24 May 2008 18:26:32 +0530

*>>
*

>> To apply uniroot I don't even know the interval values... Does numerical

*>> methods help me? Or any other method?
*

*>>
*

*>> Thanks and Regards,
*

*>> Shubha
*

*>>
*

*>> -----Original Message-----
*

*>> From: Duncan Murdoch [mailto:murdoch_at_stats.uwo.ca] Sent: Saturday, May 24,
*

*>> 2008 5:08 PM
*

*>> To: Shubha Vishwanath Karanth
*

*>> Subject: Re: [R] Solving 100th order equation
*

*>>
*

*>> Shubha Vishwanath Karanth wrote:
*

*>>
*

*>>>
*

*>>> Hi R,
*

*>>>
*

*>>>
*

*>>> I have a 100th order equation for which I need to solve the value for x.
*

*>>> Is there a package to do this?
*

*>>>
*

*>>>
*

*>>> For example my equation is:
*

*>>>
*

*>>>
*

*>>> (x^100 )- (2*x^99) +(10*x^50)+.............. +(6*x ) = 4000
*

*>>>
*

*>>>
*

*>>> I have only one unknown value and that is x. How do I solve for this?
*

*>>>
*

*>>>
*

*>>
*

*>> uniroot() will find one root. If you want all of them, I don't know what
*

*>> is available.
*

*>>
*

*>> Duncan Murdoch
*

*>>
*

expression(list())

R-help_at_r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sat 24 May 2008 - 13:07:32 GMT

Date: Sat, 24 May 2008 18:26:32 +0530

Was also wondering which theoretical method is used to solve this problem?

Thanks,

Shubha Karanth | Amba Research

Ph +91 80 3980 8031 | Mob +91 94 4886 4510
Bangalore * Colombo * London * New York * San José * Singapore * www.ambaresearch.com

-----Original Message-----

From: Gabor Grothendieck [mailto:ggrothendieck_at_gmail.com]
Sent: Saturday, May 24, 2008 6:13 PM

To: Peter Dalgaard

Cc: Shubha Vishwanath Karanth; r-help_at_stat.math.ethz.ch; Duncan Murdoch
Subject: Re: [R] Solving 100th order equation

On Sat, May 24, 2008 at 8:31 AM, Peter Dalgaard <p.dalgaard_at_biostat.ku.dk> wrote:

> Shubha Vishwanath Karanth wrote:

>> To apply uniroot I don't even know the interval values... Does numerical

> > polyroot() is built for this, but it stops at 48th degree polynomials, at > least as currently implemented. Not sure that it (or anything else) would be > stable beyond that limit. YACAS perhaps? >

Unfortunately yacas does not seem to be able to handle it:

> library(Ryacas) > x <- Sym("x") > Solve((x^100 )- (2*x^99) +(10*x^50)+(6*x ) - 4000 == 0, x)[1] "Starting Yacas!"

expression(list())

Simpler one works ok:

> Solve(x^2 - 1, x)

expression(list(x == 1, x == -1))

This e-mail may contain confidential and/or privileged i...{{dropped:10}}

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sat 24 May 2008 - 13:07:32 GMT

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