Mathematica 9 is now available
Services & Resources / Wolfram Forums / MathGroup Archive
-----

MathGroup Archive 2011

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

Search the Archive

Re: Cancel order

  • To: mathgroup at smc.vnet.net
  • Subject: [mg123266] Re: Cancel order
  • From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
  • Date: Tue, 29 Nov 2011 07:40:59 -0500 (EST)
  • Delivered-to: l-mathgroup@mail-archive0.wolfram.com
  • References: <201111291205.HAA05469@smc.vnet.net>


On 29 Nov 2011, at 13:05, =E9=81=93 =E5=8E=9A wrote:

> How can I make Sqrt[(v1^2+v2^2)(g^2+gp^2)]/Sqrt[v1^2+v2^2] simple in
> mathematica?
>

You need the assumption that the expressions under the square root are positive. So:

Assuming[g^2 + gp^2 >= 0 && v1^2 + v2^2 > 0,
   Simplify[Sqrt[(g^2 + gp^2)*(v1^2 + v2^2)]/Sqrt[v1^2 + v2^2]]]

Sqrt[g^2 + gp^2]

In particular, this will be true if everything in your expression is real:

Assuming[Element[_, Reals],
   Simplify[Sqrt[(g^2 + gp^2)*(v1^2 + v2^2)]/
       Sqrt[v1^2 + v2^2]]]

Sqrt[g^2 + gp^2]

Andrzej Kozlowski





  • References:
  • Prev by Date: Re: Ragged region boundary
  • Next by Date: Re: how to get string in sci. notation to a number?
  • Previous by thread: Cancel order
  • Next by thread: Re: Cancel order