GNU bug report logs - #4031
calc simplification problem

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Message #5 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Colin Williams <lackita <at> gmail.com>
To: bug-gnu-emacs <at> gnu.org
Subject: calc simplification problem
Date: Tue, 4 Aug 2009 10:28:58 -0400

In calc, doing `a s' simplifies "(1 + cos(x)^2 - 1) / cos(x)" to
"cos(x)^2 sec(x)", which contradicts an example in the tutorial on
rewrite rules.

Colin

Message #10 received at submit <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Jay Belanger <jay.p.belanger <at> gmail.com>
To: Colin Williams <lackita <at> gmail.com>
Cc: 4031 <at> debbugs.gnu.org, bug-gnu-emacs <at> gnu.org
Subject: Re: bug#4031: calc simplification problem
Date: Tue, 04 Aug 2009 19:44:52 -0500

Colin Williams <lackita <at> gmail.com> writes:

> In calc, doing `a s' simplifies "(1 + cos(x)^2 - 1) / cos(x)" to
> "cos(x)^2 sec(x)", which contradicts an example in the tutorial on
> rewrite rules.

So it does.  Calc needs to simplify expressions with secant (and
cosecant and cotangent) better.  I'll be out of town for the next week;
I'll fix it as soon as I get back.

Jay

Message #20 received at 4031 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Chong Yidong <cyd <at> stupidchicken.com>
To: Jay Belanger <jay.p.belanger <at> gmail.com>
Cc: Colin Williams <lackita <at> gmail.com>, 4031 <at> debbugs.gnu.org
Subject: Re: bug#4031: calc simplification problem
Date: Sat, 24 Oct 2009 15:27:55 -0400

Jay Belanger <jay.p.belanger <at> gmail.com> wrote:

> > In calc, doing `a s' simplifies "(1 + cos(x)^2 - 1) / cos(x)" to
> > "cos(x)^2 sec(x)", which contradicts an example in the tutorial on
> > rewrite rules.

> So it does.  Calc needs to simplify expressions with secant (and
> cosecant and cotangent) better.  I'll be out of town for the next week;
> I'll fix it as soon as I get back.

Hi Jay,

Did you get around to fixing this?  If so, this bug should be closed.

Message #25 received at 4031 <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Jay Belanger <jay.p.belanger <at> gmail.com>
To: Chong Yidong <cyd <at> stupidchicken.com>
Cc: Colin Williams <lackita <at> gmail.com>, 4031 <at> debbugs.gnu.org
Subject: Re: bug#4031: calc simplification problem
Date: Sat, 24 Oct 2009 15:47:11 -0500

Chong Yidong <cyd <at> stupidchicken.com> writes:
...
>> > In calc, doing `a s' simplifies "(1 + cos(x)^2 - 1) / cos(x)" to
>> > "cos(x)^2 sec(x)", which contradicts an example in the tutorial on
>> > rewrite rules.
...
> Hi Jay,
>
> Did you get around to fixing this?

Yes.

> If so, this bug should be closed.

Sorry; I'll take care of it now.

Jay

Message #30 received at 4031-done <at> emacsbugs.donarmstrong.com (full text, mbox):

From: Jay Belanger <jay.p.belanger <at> gmail.com>
To: 4031-done <at> debbugs.gnu.org
Cc: jay.p.belanger <at> gmail.com
Subject: Re: calc simplification problem
Date: Sat, 24 Oct 2009 15:58:10 -0500

> In calc, doing `a s' simplifies "(1 + cos(x)^2 - 1) / cos(x)" to
> "cos(x)^2 sec(x)", which contradicts an example in the tutorial on
> rewrite rules.

The simplification rules were adjusted, and the example was changed to
match the rules.

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