Re: How to treat this false singular point?

*To*: mathgroup at smc.vnet.net*Subject*: [mg68455] Re: How to treat this false singular point?*From*: "simon yang" <yanshanguke at 163.com>*Date*: Sat, 5 Aug 2006 03:47:02 -0400 (EDT)*References*: <eauut9$14n$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

I had made a mistake again, haha, sorry. In: Limit[(x-10)*Log[Abs[x-10]],x->10] Out: 0 Bob Hanlon wrote: > f[x_, xList_List] := Total[(x-xList)*Log[Abs[x-xList]]]; > > f[x, {x1, x2, x3}] > > (x - x1)*Log[Abs[x - x1]] + (x - x2)*Log[Abs[x - x2]] + (x - x3)*Log[Abs[x - x3]] > > a singularity will exist for each value of x in xList; therefor, f[xn, xList] cannot have the value 1 > > f[5. - 10^-15, Range[5]] > > 10.2273 > > Plot[f[x,Range[5]],{x,-1,5}]; > > > Bob Hanlon > > ---- simon yang <yanshanguke at 163.com> wrote: > > Dear everyone, > > I have a function: > > f[x_]:=(x-x1)Log[Abs[x-x1]] + (x-x2)Log[Abs[x-x2]] + ... + > > (x-xn)Log[Abs[x-xn]], > > {x1,x2,...,xn}={100,200,300,...} for instance > > How to get value: f[x] as there are different singular at different x? > > I know at x=xn, f[x]==1, But Mathematica return: "Indeterminate", What > > should I do? > > what others do in C++, Fortran ? > >