Re: entering an equation

*To*: mathgroup at smc.vnet.net*Subject*: [mg21603] Re: entering an equation*From*: "Allan Hayes" <hay at haystack.demon.co.uk>*Date*: Sun, 16 Jan 2000 22:43:49 -0500 (EST)*References*: <85s1gr$ajj@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Mark The message tells you what the difficulty is for Mathematica. It arrises since Log[2,x] is complex for x<0, Indeterminate for x=0 (though it may be defined as -Infinity), negative for 0<x<1, zero for x =1, positive for x>1 Check by evaluating Table[{x, Log[2, Log[2, x]]}, {x, -1, 2, .2}] // ColumnForm "Mark Woolard" <mark at ratbyte.com> wrote in message news:85s1gr$ajj at smc.vnet.net... > I am trying to plot a series of functions in Mathematica...one is giving me > trouble. I need : ln2 (ln2 x) > > I enter: Log[2, Log[2,x]] > > and I get: > > is not a machine-size real \ > number at \!\(x\) = \!\(4.1666666666666667`*^-7\)." > > Does anyone have any suggestions? > >