Re: number dot (with space)

*To*: mathgroup at smc.vnet.net*Subject*: [mg99822] Re: number dot (with space)*From*: Bill Rowe <readnews at sbcglobal.net>*Date*: Fri, 15 May 2009 04:20:49 -0400 (EDT)

On 5/14/09 at 1:40 AM, emin.gahramanov at deakin.edu.au (Emin Gahramanov) wrote: >Hi guys, sorry for the silly question (I am a Mathematica dummy). I >have integrated out an expression, and I do not know how to >interpret the term like this: (-1. g + r)^4) What throws me off is >"1. g" (g is a parameter), what is that dot after one >and there is also a SPACE after the dot and before "g" symbol. >Sometimes I get smth. like "1. r" what is that supposed to mean? If >r=2, then how to interpret the latter? Is it 1.2?? Or? Thanks. The expression "1. g" is the product of 1 and g. Mathematic uses a space in expressions like this to represent multiplication. The value 1. will be a machine precision number that isn't quite 1. For example, here is an operation that will generate an equivalent expression In[4]:= y = (1. + 1/10^8)*x Out[4]= 1. x And I can show the constant isn't quite 1 by doing In[5]:= y[[1]] - 1 Out[5]= 1.*10^-8