Re: Simplify further

• To: mathgroup at smc.vnet.net
• Subject: [mg61809] Re: [mg61791] Simplify further
• From: Bob Hanlon <hanlonr at cox.net>
• Date: Mon, 31 Oct 2005 01:17:04 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

```FullSimplify eliminates the Sqrt

\$Version

5.2 for Mac OS X (June 20, 2005)

f[x_] := c/(x - p) + Conjugate[c]/(x - Conjugate[p])

soln=Simplify[Solve[D[f[x],x]==0,x]];

FullSimplify[f[x]/.soln]

{(Re[c]^2*Sign[c])/(Im[c]*Im[p]*Sign[c] -
c*Im[p]*Sign[Im[p]]),
Re[c]^2/(Im[p]*(Im[c] + Conjugate[c]*Sign[c]*
Sign[Im[p]]))}

Bob Hanlon

>
> From: "Thomas Schmelzer" <thomas.??? at balliol.ox.ac.uk>
To: mathgroup at smc.vnet.net
> Date: 2005/10/30 Sun AM 12:43:20 EDT
> Subject: [mg61809] [mg61791] Simplify further
>
> Hi experts,
>
> Let
>
> f[x_] := c/(x - p) + c\[Conjugate]/(x - p\[Conjugate])
>
> I am interested in local extrema
>
> Solve[D[f[x], x] == 0, x]
>
> Mathematica gives me a list.
>
> I plug those values into f again.
>
> Using the Simplify command I get expression as
>
> sqrt(- c conjugate c ( p - conjugate p ) ^2 )
>
> Is there a way that Mathematica simplifies that to
>
> 4*(abs (c))^2  (Im p)^2
>
> cheers
>
> Thomas
>
>
>
>
>

```

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