Re: odd mathematica blindspot

*To*: mathgroup at smc.vnet.net*Subject*: [mg56484] Re: [mg56468] odd mathematica blindspot*From*: Bob Hanlon <hanlonr at cox.net>*Date*: Tue, 26 Apr 2005 21:52:39 -0400 (EDT)*Reply-to*: hanlonr at cox.net*Sender*: owner-wri-mathgroup at wolfram.com

$Version 5.1 for Mac OS X (January 27, 2005) Off[Solve::ifun]; x/.(Solve[(999999999999/10000000000000)^x\[Equal].5,x]//Flatten) 0.30103 x /. (Solve[(999999999999/10000000000000)^x\[Equal]1/2,x]//Flatten) Log[2]/Log[10000000000000/999999999999] %//N 0.30103 Bob Hanlon > > From: Edward Peschko <esp5 at pge.com> To: mathgroup at smc.vnet.net > Date: 2005/04/26 Tue AM 01:33:53 EDT > Subject: [mg56484] [mg56468] odd mathematica blindspot > > 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 > >