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Re: A simple problem

  • To: mathgroup at smc.vnet.net
  • Subject: [mg25807] Re: [mg25786] A simple problem
  • From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
  • Date: Sat, 28 Oct 2000 01:41:01 -0400 (EDT)
  • Sender: owner-wri-mathgroup at wolfram.com

You can get a part of what you want (in Mathematica 4.0 only).

In[2]:=
Simplify[Solve[f, t], {p > 0, a > 0}]

Out[2]=
{{t -> -(Sqrt[2]*Sqrt[p/a])}, {t -> Sqrt[2]*Sqrt[p/a]}}

However, you can't really make the 2 go under the square root sign (without
using Hold or HoldForm) because Mathematica will take it out again, since:

In[3]:=
Sqrt[2p]

Out[3]=
Sqrt[2] Sqrt[p]

on 00.10.25 4:53 PM, Paul Lutus at nospam at nosite.com wrote:

> I have a very simple notation problem I cannot solve (because of my limited
> knowledge of Mathematica).
> 
> Example -- an equation from physics:
> 
> f := a * t^2 / 2 - p == 0
> 
> Now I want to create the different forms of this equation, such as:
> 
> Solve[f,t]
> 
> which produces:
> 
> sqrt(2) * sqrt(p) / sqrt(a)
> 
> Okay, the correct general solution. What I really wanted was the limited
> solution ( sqrt(2p/a) ). I know I need to say "assume all the variables are
>> = 0", but I can't figure out how to express this.
> 
> I've tried applying a number of different constraints without success.
> 
> Hey -- I warned you. Simple problem. :)
> 
> --
> 
> Paul Lutus
> www.arachnoid.com
> 
> 
> 
> 

-- 
Andrzej Kozlowski
Toyama International University
JAPAN

http://platon.c.u-tokyo.ac.jp/andrzej/
http://sigma.tuins.ac.jp/



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