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Re: Q: Solve gives complex solution where there is a noncomplex solution how to get the last one?

• To: mathgroup at smc.vnet.net
• Subject: [mg50320] Re: [mg50300] Q: Solve gives complex solution where there is a noncomplex solution how to get the last one?
• From: jmt <jmt at dxdydz.net>
• Date: Fri, 27 Aug 2004 02:57:25 -0400 (EDT)
• Organization: dxdydz
• References: <200408261050.GAA16310@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Note that 0.5 is different from 1/2 :

The following expression will lead to your expectation :


Solve[x y/(1+y^2)^(1/2)==a,y]


On Thursday 26 August 2004 12:50, Dick Barends wrote:
> Hello,
>
> The following line
>
> Solve[x y / ( 1 + y^2 )^0.5 == a, y]
>
> Gives a complex solution : (0.+ i )a / (a^2 - x^2)^0.5
> Which is correct but could be simpler, not complex
>
> The solution I expected is: a/(x^2 - a^2)^0.5
>
> How can I instruct Mathematica (Solve) to give the simple solution
> directly.
>
> kind regards
> Dick Barends

• References:
  • Q: Solve gives complex solution where there is a noncomplex solution how to get the last one?
    • From: "Dick Barends" <dick.barends@wxs.nl>