Re: why is this happening?

*To*: mathgroup at smc.vnet.net*Subject*: [mg99223] Re: why is this happening?*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Thu, 30 Apr 2009 06:22:50 -0400 (EDT)*Organization*: Uni Leipzig*References*: <gt9aq0$q7o$1@smc.vnet.net>*Reply-to*: kuska at informatik.uni-leipzig.de

Hi, and you are sure that you not mean Solve[k2/k1 + ld^2 + ld == 0, ld] vs Solve[k1 ld + k2 + k1*ld^2 == 0, ld] or do you just like to ask why Mathematica return different answers for nonequivalent input ? Regards Jens sean_incali at yahoo.com wrote: > Consider the following. > > Solve[k1 ld + k1 k2 + ld^2 == 0, ld] > > vs > > Solve[k2/k1 + ld^2 + ld == 0, ld] > > > I expected to get the output I got from the first code. > >>From the second code, I was expecting something along the lines of > > ld ->-1 + (SquareRoot[1 - 4 (k2/k21)])/2 > ld -> -1 - (SquareRoot[1 - 4 (k2/k21)])/2 > > since that is the answer. > > Why is Mathematica turning the second scaled equation into the > unscaled one in the first before solving it? > > Thanks for any insight. > > Sean > >