AW: System for which Solve and NSolve both fail

*To*: mathgroup at smc.vnet.net*Subject*: [mg30588] AW: [mg30572] System for which Solve and NSolve both fail*From*: Matthias.Bode at oppenheim.de*Date*: Thu, 30 Aug 2001 03:51:34 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

Hello Ben, straight from the Help Browser: 1. "Solve deals primarily with linear and polynomial equations." 2. "NSolve[aa, a, . a, aa, a, . a] solves a system of polynomial equations." Use FindRoot, it works, I tried it. Best regards, Matthias. -----Ursprungliche Nachricht----- Von: Ben Langton [mailto:ben at spam.bugs.me.quickmath.com] Gesendet: Mittwoch, 29. August 2001 07:40 An: mathgroup at smc.vnet.net Betreff: [mg30572] System for which Solve and NSolve both fail Hi, I noticed that Mathematica seems unable to solve this system of equations : 3^x + 3^y = 90 x + y = 6 With a bit of thought, you can see by inspection that the solutions are {x , y} = {2 , 4} or {4 , 2} However, when I use the commands Solve[{3^x+3^y==90,x+y==6},{x,y}] or NSolve[{3^x+3^y==90,x+y==6},{x,y}] I get a warning message starting with Solve::incnst: Inconsistent or redundant transcendental equation Can anyone shed some light on what is going on here? Any way to get around this problem? (I am using Mathematica v 3.0.0.0 under Mac OS 9.2.1, although I believe a similar thing occurs under v 4.x) Regards, Ben Langton http://www.quickmath.com/