You have two values for x = 10000, y = 160 then y = 20. Maybe you should fix that.
Rich
--------------------------------------------------
From: "Robert Dodier" <robert.dodier at gmail.com>
Sent: Friday, June 11, 2010 11:23 AM
To: "Hugo Coolens" <coolens at kahosl.be>
Cc: <maxima at math.utexas.edu>
Subject: Re: [Maxima] problem with fitting data using lsquares
> On 6/11/10, Hugo Coolens <coolens at kahosl.be> wrote:
>
>> m:matrix([100,16000],[200,8000],[500,3636],[1000,1818],[2000,870],[5000,323],[10000,160],[20000,83],[50000,33],[10000,20]);
>> load (lsquares)$
>> lsquares_estimates
>> (m,[x,y],y=sqrt((a^2)+((10e7/(2*pi*x*b))^2)),[a,b],initial=[10,10]);
>
> I think you want %pi instead of pi there. Otherwise the expression
> won't evaluate to a number.
>
> best,
>
> Robert Dodier
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