[Maxima-bugs] [ maxima-Bugs-815833 ] asin(x) and acos(x) plainly wrong

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Bugs item #815833, was opened at 2003-10-01 13:12
Message generated for change (Comment added) made by villate
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Submitted By: Jaime E. Villate (villate)
Assigned to: Nobody/Anonymous (nobody)
Summary: asin(x) and acos(x) plainly wrong

Initial Comment:
The asin and acos functions are compete wrong. Using

Maxima 5.9.0  with GCL (Debian's package maxima 5.9.0-11):



(C1) asin(0.5);

(D1)                                  0.5

(C2) asin(0.9);

(D2)                                  0.9

(C3) asin(1);

                                      %PI

(D3)                                ---

                                       2



In fact, plot2d(asin(x), [x, -4, 4]) shows that asin

has nothing to do with the arcsine function (same

problem with acos).

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>Comment By: Jaime E. Villate (villate)
Date: 2003-10-01 18:22

Message:
Logged In: YES 
user_id=28692

Yeah, I also have the recent GCL version:



(C1) build_info();

Maxima version: 5.9.0

Maxima build date: 19:17 9/9/2003

host type: i686-pc-linux-gnu

lisp-implementation-type: Kyoto Common Lisp

lisp-implementation-version: GCL-2-6.0999999999999996



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Comment By: James Amundson (amundson)
Date: 2003-10-01 18:12

Message:
Logged In: YES 
user_id=28457

Wow. That is very bad.  The problem seems to be a bad interaction 
between (presumably) newer versions of GCL and Maxima. The 
GCL-Maxima 5.9.0 we distribute in RPM does not have the problem: 
 
------------------------------------------------------------------ 
(C1) build_info(); 
 
 
Maxima version: 5.9.0 
Maxima build date: 22:24 2/9/2003 
host type: i386-redhat-linux-gnu 
lisp-implementation-type: Kyoto Common Lisp 
lisp-implementation-version: GCL-2-5.0 
 
(D1) 
(C2) asin(0.5); 
 
(D2)                            0.5235987755983 
------------------------------------------------------------------ 
 
The GCL-Maxima I have in my development area (which I think is 
identical to the current cvs), when compiled with a recent cvs version 
of GCL, does have the problem: 
------------------------------------------------------------------ 
(C1) build_info(); 
 
 
Maxima version: 5.9.0.1cvs 
Maxima build date: 7:43 9/25/2003 
host type: i686-pc-linux-gnu 
lisp-implementation-type: Kyoto Common Lisp 
lisp-implementation-version: GCL-2-6.0999999999999996 
 
(D1) 
(C2) asin(0.5); 
 
(D2)                                  0.5 
------------------------------------------------------------------ 
 
Please send the build_info() output for your Maxima. 
 

----------------------------------------------------------------------

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