Re: Coaxing N[] to work

*To*: mathgroup at smc.vnet.net*Subject*: [mg73412] Re: Coaxing N[] to work*From*: dh <dh at metrohm.ch>*Date*: Thu, 15 Feb 2007 05:11:34 -0500 (EST)*References*: <equo6r$in0$1@smc.vnet.net>

Hi, N can not create additional precission. You calculated lambda with machine precission! Daniel p at dirac.org wrote: > Sometimes N[,] doesn't appear to work. Like here: > > > x = {2.0, 3.0, 5.0}; > A = { {6.0, 2.0, 1.0}, {2.0, 3.0, 1.0}, {1.0, 1.0, 1.0} }; > For[ k=0, k<15, ++k, > lambda = x.A.x/(x.x); > y = LinearSolve[A,x]; > x = y / Norm[y,Infinity]; > ] > N[lambda, 30] > > > The output is: > > Out[5]= 0.578933 > > I was expecting 30 digits. Why did N[] ignore my request for 30 digits? >