MathGroup Archive 2008

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

Search the Archive

Re: smart change of variables?



Hi barrow,

you may achieve this using e.g. Solve:

Solve[{expr==(k1+2 k2) (p1+2 

p2)p1+p2==k1+k2,s==(p1+p2)^2,t==(-k1+p1)^2,u==(-k2+p1)^2,},expr,{p1,p2,k1,k2}]

hope this helps, Daniel



Barrow wrote:

> Dear all,

> 

> I have a arithmetic problem.

> I have an expression expr = (p1 + 2*p2)*(k1 + 2*k2)

> where p1 + p2 = k1 + k2

> I wanna make the following change of variables,

> s = (p1 + p2)^2

> t = (p1 - k1)^2

> u = (p1 - k2)^2

> 

> Is it possible to tell Mathematica to express expr

> in terms of s, t, and u automatically?

> 

> Thanks so much.

> any ideas would be appreciated.

> Sincerely Barrow

> 




  • Prev by Date: Re: How to solve this simple equation?
  • Next by Date: Re: Package to 'graft' Lists onto Matrices
  • Previous by thread: Re: smart change of variables?
  • Next by thread: Re: smart change of variables?