Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Non-algebraic solution

  • To: mathgroup at smc.vnet.net
  • Subject: [mg52421] Re: [mg52399] Non-algebraic solution
  • From: DrBob <drbob at bigfoot.com>
  • Date: Fri, 26 Nov 2004 06:20:26 -0500 (EST)
  • References: <200411260604.BAA24122@smc.vnet.net>
  • Reply-to: drbob at bigfoot.com
  • Sender: owner-wri-mathgroup at wolfram.com

It can be solved and plotted for some values of the parameters.

For instance:

Clear[x, y]
Block[{a = 3,
  b = 2, c = 1, d = 4, equation = Log[y/a] + b*Log[c + y/d] == -x},
     Solve[equation, y]
     ];
y[x_] = y /. First@%
Plot[y@x, {x, -25, 10}]

Bobby

On Fri, 26 Nov 2004 01:04:27 -0500 (EST), B.Ravinder <ravi at crest.ernet.in> wrote:

> Dear all,
> I want to plot the following type of logarithmic equation having
> dependent variable y and independent variable x.
>
> Log[y/a] + b*Log[c+y/d] = -x
>
> where a,b,c and d are some arbitrary constants.
>
> First I tried to solve the equation for y using Solve function in
> Mathematica 4.2, but got the following error
> message:
> Solve:: tdep :
> The equations appear to involve the variables to be solved
> for in an essentially non-algebraic way.
>
>
> Could someone please guide me as to how do we solve such equation
> with/without Mathematica.
>                              or
> If possible, how to obtain y vs. x plot in Mathematica without soving them
> exactly.
> Waiting for the kind resonse.
>
> Regards,
> Ravi
>
>
>
>



-- 
DrBob at bigfoot.com
www.eclecticdreams.net


  • Prev by Date: Re: Speeding UP Indexing and Joining of Different Size Rectangular Matrixes
  • Next by Date: filtering of a graphics
  • Previous by thread: Non-algebraic solution
  • Next by thread: Re: Non-algebraic solution