MathGroup Archive 2009

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

Search the Archive

Re: Re: Cannot solve very simple equation.

  • To: mathgroup at smc.vnet.net
  • Subject: [mg105801] Re: [mg105725] Re: Cannot solve very simple equation.
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Sun, 20 Dec 2009 06:51:38 -0500 (EST)
  • References: <hgaftl$qba$1@smc.vnet.net> <200912161134.GAA27832@smc.vnet.net>

You can solve the equation with Reduce as long as you restrict it to a 
finite interval (or rectangle in C). E.G.

N[Reduce[x^2 + 1 == 2^x && -10 < x < 10, x]]

 x == 0. || x == 1. || x == 4.257461914447932

Andrzej Kozlowski

On 16 Dec 2009, at 20:34, Alois Steindl wrote:

> negatron <lokieffect at gmail.com> writes:
>
>> NSolve[x^2 + 1 == 2^x]
>>
>> "Solve::tdep: "\!\(\*
>> StyleBox[\"\\\"The equations appear to involve the variables to be
>> solved for in an essentially non-algebraic way.\\\"\", \"MT\"]\) ""
>>
>> Am I forgetting something trivial here?
>>
> Hello,
> from the Help page:
> 	NSolve[lhs==rhs,var]
> gives a list of numerical approximations to the roots of a polynomial 
equation.
>
> Although your equation looks quite simple, it isn't polynomial.
>
> Alois
>
>
> --
> Alois Steindl,                           Tel.: +43 (1) 58801 / 32558   
  
> Inst. for Mechanics and Mechatronics     Fax.: +43 (1) 58801 / 32598
> Vienna University of Technology,         A-1040 Wiedner Hauptstr. 8-10 
 
>



  • Prev by Date: Re: CellChangeTimes?
  • Next by Date: Integrate[Piecewise] Confusion
  • Previous by thread: Re: Cannot solve very simple equation.
  • Next by thread: MathKernel7.0 Densityplot showing blank