Re: Inverse function warnings
- To: mathgroup at smc.vnet.net
- Subject: [mg99238] Re: Inverse function warnings
- From: dh <dh at metrohm.com>
- Date: Thu, 30 Apr 2009 06:25:34 -0400 (EDT)
- References: <gt90og$l55$1@smc.vnet.net>
Hi,
your equation is a transcendental equation with infinitely many
solutions. Reduce gets them all. You get them by setting C[1] to some
arbitrary integer.
You may eliminate the warning by:
Quiet@Solve[3^(2 x) - 12 (3^x) + 27 == 0, x]
Daniel
davef wrote:
> When I execute this in Mathematica 7:
>
> Solve[3^(2 x) - 12 (3^x) + 27 == 0, x]
>
> I get this:
>
> Solve::ifun: Inverse functions are being used by Solve, so some solutions may not be found; use Reduce for complete solution information. >>
>
> {{x->1},{x->2}}
>
>
> 1 amd 2 are proper solutions but is it possible to avoid the warning?
>
> If I use Reduce:
>
> Reduce[3^(2 x) - 12 (3^x) + 27 == 0, x]
>
> I get a set of 1 and 2 added to some imaginary number terms that I don't quite understand.
>
> I guess my question is: why would the use of inverse functions be so unreliable a solution as to necessitate a warning? And in the interest of clean output, can the warning be supressed other than by deleteing the cell?
>
> Thanks
>