[LON-CAPA-users] Maxima is being fussy

[Seema Ali]

I think the version I have on my computer is different from the one use on the Lon Capa server.  It worked fine in the command line.  Below are the Maxima commands I used.

I guess with my inexperience with Maxima, I'm worried that there might be another case that Maxima will mark a correct answer wrong.  Will the triple trigsimp(trigreduce()) trick always work?


(%i30) g(x) := 1/3 * (8 + (x-3)^3);
                                   1             3
(%o30)                     g(x) := - (8 + (x - 3) )
                                   3
(%i31) h(x) := 8/3 + ((x-3)^3)/3;
                                                3
                                     8   (x - 3)
(%o31)                       h(x) := - + --------
                                     3      3
(%i32) is(trigsimp(trigreduce(g(x) - h(x)=0)));
(%o32)                               true
(%i33) is(trigsimp(trigreduce(h(x) - g(x)=0)));
(%o33)                               true
(%i34) h(x) := (8 + (x-3)^3)/3;
                                                3
                                     8 + (x - 3)
(%o34)                       h(x) := ------------
                                          3
(%i35) is(trigsimp(trigreduce(g(x) - h(x)=0)));
(%o35)                               true
(%i36) is(trigsimp(trigreduce(h(x) - g(x)=0)));
(%o36)                               true
(%i37) 

-----Original Message-----
From: lon-capa-users-bounces at mail.lon-capa.org on behalf of Gerd Kortemeyer
Sent: Tue 2/21/2012 6:36 PM
To: Discussion list for LON-CAPA users
Subject: Re: [LON-CAPA-users] Maxima is being fussy
 
Hi,

On Feb 21, 2012, at 6:56 PM, Seema Ali wrote:

> I don't really understand how the abs()<0.0000001 tolerance works for an algebraic expression.

There should not be a need for a tolerance.

>  So I decided to go nuts with the trigsimp() and trigreduce() functions.  I applied it to both functions and then did the subtraction and applied it again.
> 
> is(trigsimp(trigreduce(trigsimp(trigreduce(RESPONSE[1]))- trigsimp(trigreduce(g(x)))))=0);
> 
> It seems to be working, but is this approach full proof?

It does seem weird that this would be needed. Can you use MAXIMA from the command line, enter your previous expressions by hand, and see what MAXIMA says?

- Gerd.
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