no numeric evaluation of ln(1) after replacing in ln(r/a) by r=a
Subject: no numeric evaluation of ln(1) after replacing in ln(r/a) by r=a
From: reyssat
Date: Tue, 16 Mar 2010 22:05:52 +0100
Le 16/03/2010 21:56, alberich a ?crit :
> Hello,
>
> I couldn't find how to further simplify w in the example below. I'd
> expect a result like w_1+c_2*r_a^2+c_1 but not
> w_1+ln(1)*c_4*r_a^2+c_2*r_a^2+ln(1)*c_3+c_1
>
> (%i2) w: c_1+c_2*r^2+c_3*ln(r/r_a)+c_4*r^2*ln(r/r_a)+w_1;
> (%i45) w;
> 2 r r 2
> (%o45) w_1 + c_4 r ln(---) + c_3 ln(---) + c_2 r + c_1
> r_a r_a
> (%i46) ev(w,numer,r=r_a);
> 2 2
> (%o46) w_1 + ln(1) c_4 r_a + c_2 r_a + ln(1) c_3 + c_1
> (%i47)
maxima doesn't know ln, use log instead
Eric
>
> Thanks for your help
> Alain
>
>
> _______________________________________________
> Maxima mailing list
> Maxima at math.utexas.edu
> http://www.math.utexas.edu/mailman/listinfo/maxima
>