Bugs item #635045, was opened at 20021107 09:31
Message generated for change (Comment added) made by robert_dodier
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>Category: Lisp Core
Group: None
>Status: Closed
>Resolution: Fixed
Priority: 5
Submitted By: Barton Willis (willisb)
Assigned to: Nobody/Anonymous (nobody)
Summary: derivatives of acsc, ...
Initial Comment:
Maxima's formulae for the derivatives of acsc, asec,
acsch,
and asech are incorrect in the left half plane. To
illustrate, we should have asin(1/x)  acsc(x) = 0
for all x # 0; however,
(C2) ratsimp(diff(asin(1/x)  acsc(x),x));
(D2) SQRT(x^21)*(ABS(x)x)/(x^4x^2)
This only vanishes for x > 0. I've attached
a diff file for comm.lisp that fixes these
problems. And I attached an rtest file
that tests the derivatives of the inverse
trig functions.
Barton

>Comment By: Robert Dodier (robert_dodier)
Date: 20060630 21:17
Message:
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user_id=501686
Problem shown here is OK now (5.9.3cvs):
ratsimp(diff(asin(1/x)  acsc(x),x)); => 0
Patch was applied to src/comm.lisp and committed as r1.12.
Test cases found their way into the cvs as
tests/rtest_diff_invtrig.mac and 5.9.3cvs passes all tests.
Closing this report as fixed.

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