Re: How to treat this false singular point?

*To*: mathgroup at smc.vnet.net*Subject*: [mg68452] Re: How to treat this false singular point?*From*: "simon yang" <yanshanguke at 163.com>*Date*: Sat, 5 Aug 2006 03:46:57 -0400 (EDT)*References*: <eauut9$14n$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

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 Sorry, I had made a mistake, I mean the limit of (x-xn)Log[x-xn]==1 when x->xn and x>xn. The f[x] is a part of another function g[x], Mathematica didn't get this value when met x=xn which I thought it should.