MathGroup Archive 2010

[Date Index] [Thread Index] [Author Index]

Search the Archive

Mathematica Collect function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg110680] Mathematica Collect function
  • From: Minh <dminhle at gmail.com>
  • Date: Fri, 2 Jul 2010 02:55:23 -0400 (EDT)

Given that:
Expand[((1 + Sqrt[2]) i - 1)/4*(P10 - P11) - (1 + Sqrt[2] + i)/
   4*(P20 - P21)]

will output
-(P10/4) + (i P10)/4 + (i P10)/(2 Sqrt[2]) + P11/4 - (i P11)/4 - (
 i P11)/(2 Sqrt[2]) - P20/4 - P20/(2 Sqrt[2]) - (
 i P20)/4 + P21/4 + P21/(2 Sqrt[2]) + (i P21)/4

How do I get from:
-(P10/4) + (i P10)/4 + (i P10)/(2 Sqrt[2]) + P11/4 - (i P11)/4 - (
 i P11)/(2 Sqrt[2]) - P20/4 - P20/(2 Sqrt[2]) - (
 i P20)/4 + P21/4 + P21/(2 Sqrt[2]) + (i P21)/4

back to
((1 + Sqrt[2]) i - 1)/4*(P10 - P11) - (1 + Sqrt[2] + i)/
   4*(P20 - P21)

I've tried using the Collect function as follows:
Collect[-(P10/4) + (i P10)/4 + (i P10)/(2 Sqrt[2]) + P11/4 - (i P11)/
  4 - (i P11)/(2 Sqrt[2]) - P20/4 - P20/(2 Sqrt[2]) - (i P20)/4 + P21/
  4 + P21/(2 Sqrt[2]) + (i P21)/4, {(P10 - P11), (P20 - P21)}]
but it doesn't seem to collect the terms {(P10 - P11), (P20 - P21)}.

Got any suggestions?


  • Prev by Date: Re: Sum of terms --> list
  • Next by Date: Re: Problems running Mathematica and WordMS together in Win7
  • Previous by thread: Re: boolean variable with contours
  • Next by thread: Re: Mathematica Collect function