MathGroup Archive 2005

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

Search the Archive

Re: odd mathematica blindspot


Hi,

try

Solve[(999999999999/10000000000000)^x == 1/2, x]

and don't mix floating point numbers with symbolic
calculations.

Regards
  Jens

"Edward Peschko" <esp5 at pge.com> schrieb im 
Newsbeitrag news:d4klbs$eg7$1 at smc.vnet.net...
> hey all,
>
> I was wondering why the following didn't output 
> any solutions. I'd think
> it would be easy:
>
> Solve[(999999999999/10000000000000)^x == .5, x]
>
> It gives no solutions. What's really odd is when 
> you say:
>
> Solve[(999/1000)^x==.5, x]
>
> which *does* give solutions, in the form:
>
> {{x -> 692.801... }}
>
> Also, just curious, but how do you extract 'x' 
> from the above?
> Say I wanted to plug the above solution into 
> another equation..
> In perl I'd say something like:
>
> y = Solve[(999/1000)^x == .5, x];
>
> 3 * y->{x}  # replaces with 692.81
>
> etc. etc.
>
> but this doesn't seem to work. How do you access 
> parts of a mathematica
> datastructure/hash?
>
> And finally, how do you set values with the tty? 
> ie: suppose my backspace and
> delete key aren't working with math.exe (they 
> aren't) and I want them to
> delete typos. In unix this would be stty erase 
> ^H. In mathematica...?
>
> Thanks much for any help,
>
> Ed
> 



  • Prev by Date: Re: simplifying ulam spiral code
  • Next by Date: Re: Compile. Not again
  • Previous by thread: Re: odd mathematica blindspot
  • Next by thread: Re: odd mathematica blindspot