Subject: Maxima: trigsimp() in Maxima 5.12 v 5.10/5.9.1
From: Raymond Toy
Date: Mon, 23 Jul 2007 21:30:39 -0400
C. Frangos wrote:
> (2) It appears that in Maxima 5.10/5.9.1, trigsimp() assumes that expres1 =
> 2*sin(delta3)*Lo1+cos(delta3)*Lc > 0 in y1.
>
> It then simplifies sqrt(expres1^2) to expres1.
>
> In Maxima 5.12, trigsimp() does not do this.
>
>
Yes, this was a bug in trigsimp, prior to 5.12. sqrt(x^2) should not
simplify to x because it's wrong in general.
> (3) For this application, the assumption expres1 > 0 is physically correct.
> What is the Maxima command to implement this assumption explicitly ?
>
>
assume(expr > 0);
Don't know if that will allow maxima convert your particular
sqrt(expr^2) to expr, though. You could also try radcan(). See the
documentation for radcan.
Ray