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MathGroup Archive 2007

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Re: Sometimes <space> means multiple , sometimes not

  • To: mathgroup at smc.vnet.net
  • Subject: [mg75351] Re: Sometimes <space> means multiple , sometimes not
  • From: dh <dh at metrohm.ch>
  • Date: Thu, 26 Apr 2007 03:31:09 -0400 (EDT)
  • References: <f0n6su$p9d$1@smc.vnet.net>


Hi,

note that "-" can denote two different operators:

if there is an operand on both sides of "-" it means "Subtract"

if there is no operand to the left it means "Minus"

Futher "+" with operands on both sides means Plus, with only one operand 

to the right is the Identity.

Further, two operand separated by a space "*" means Multiply.

hope this helps, Daniel





siewsk at bp.com wrote:

> As a newbie, I was taught that <space> character in Mathematica means

> multiple. But sometimes it does not.

> 

> For example:

> 

> 4<space>2  gives 8

> 

> but

> 

> -4<space>-2 does not give -8

> 

> This strange behavior can be show below

> 

> In[1]:= 4 2   (* 4<space>2 *)

> Out[1]= 8

> 

> In[2]:= 4 +2   (* 4<space>+2 *)

> Out[2]= 6

> 

> In[3]:= +4 2   (* +4<space>2 *)

> Out[3]= 8

> 

> In[4]:= +4 +2   (* +4<space>+2 *)

> Out[4]= 6

> 

> In[5]:= +4 -2  (* +4<space>-2 *)

> Out[5]= 2

> 

> In[6]:= 4 -2   (* 4<space>-2 *)

> Out[6]= 2

> 

> In[7]:= -4 -2  (* -4<space>-2 *)

> Out[7]= -6

> 

> In[8]:= -4 2  (* -4<space>2 *)

> Out[8]= -8

> 

> 




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