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# Edit detail for #333 asin 1.0 over Complex Float fails revision 2 of 2

 1 2 Editor: kratt6 Time: 2007/12/20 02:09:52 GMT-8 Note: See #138

added:

From kratt6 Thu Dec 20 02:09:52 -0800 2007
From: kratt6
Date: Thu, 20 Dec 2007 02:09:52 -0800
Subject: See #138
Message-ID: <20071220020952-0800@axiom-wiki.newsynthesis.org>

Category: Axiom Mathematics => Axiom Library
Status: open => duplicate



 Submitted by : (unknown) at: 2007-11-17T22:28:24-08:00 (15 years ago) Name : Axiom Version : default friCAS-20090114 Axiom-20050901 OpenAxiom-20091012 OpenAxiom-20110220 OpenAxiom-Release-141 Category : Axiom Aldor Interface Axiom Compiler Axiom Library Axiom Interpreter Axiom Documentation Axiom User Interface building Axiom from source lisp system MathAction Doyen CD Reduce Axiom on Windows Axiom on Linux Severity : critical serious normal minor wishlist Status : open closed rejected not reproducible fix proposed fixed somewhere duplicate need more info Optional subject :   Optional comment :

The first real calculus is right, the second fails.

axiom
asin 1.0
 (1)
Type: Float
axiom
asin (1.0+0*%i)
>> Error detected within library code:
catdef: division by zero

The problem is perhaps line 162 of trigcat.spad. There is no test for the ... / sqrt (1-x^2) in asin definition.

asin x == atan(x/sqrt(1-x**2))

## patch possible. --Francois Maltey, Fri, 05 Jan 2007 07:57:48 -0600 replyI propose to remplace in asin x == atan (x/sqrt(1-x**2)) in trigcat.spad line 162 by

asin x == x=1 => 2atan 1 x=-1 => -2atan 1 atan(x/sqrt(1-x**2))

The result seems right...

Category: Axiom Mathematics => Axiom Library Status: open => duplicate