[R] Solving equations

Berend Hasselman bhh at xs4all.nl
Mon Sep 8 08:51:38 CEST 2014


On 08-09-2014, at 06:55, Mohan Radhakrishnan <radhakrishnan.mohan at gmail.com> wrote:

> No. I was not looking for an answer to that question. I wasn't clear :-) I
> already code using Octave and R to solve ML algorithms.
> 
> I am trying to understand  how R packages can help us to solve such
> equations using LU decomposition etc. The question was about using R with
> these math algorithms.
> 

It’s still unclear what you want.
Look at

?solve

The solution to your simultaneous system of linear equations is x=0 and w=0.

Berend

> Mohan
> 
> On Mon, Sep 8, 2014 at 12:31 AM, Rui Barradas <ruipbarradas at sapo.pt> wrote:
> 
>> Hello,
>> 
>> Inline.
>> 
>> Em 07-09-2014 09:54, Mohan Radhakrishnan escreveu:
>> 
>>> Hi,
>>>          I code R to parse data but not for solving equations. So this is
>>> my first such problem. It is a programming puzzle.
>>> 
>>> I have these two equations.
>>> 
>>> 1)    4x - 3w = 0
>>> 2)    8x - 7w =0
>>> 
>>> I know the value of x and w for
>>> 
>>> equation 1).  x = 3 and w = 4
>>> equation 2).  x = 7 and w = 8
>>> 
>> 
>> Why? Any of those equations defines a straight line, not a point. Those
>> two points are just one of the infinitely many solutions.
>> 
>> Your equations are equivalent to
>> eq1) w = 4/3x
>> eq2) w = 8/7x
>> 
>> the equations of straight lines passing through the origin (no independent
>> term).
>> 
>> 
>>> I also know how to write more equations based on data available in the
>>> puzzle.
>>> 
>>> How do I solve a set of such equations ? I need to find out the values of
>>> x
>>> and w for each such equation.
>>> 
>> 
>> There are packages to solve simultaneous equations but I've never used
>> them.
>> 
>> Hope this helps,
>> 
>> Rui Barradas
>> 
>>> 
>>> I know that here the equations are simple because the puzzle can be
>>> simplfied.
>>> 
>>> 
>>> Thanks,
>>> Mohan
>>> 
>>>        [[alternative HTML version deleted]]
>>> 
>>> ______________________________________________
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>>> posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>> 
>>> 
> 
> 	[[alternative HTML version deleted]]
> 
> ______________________________________________
> 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.



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