[Maxima-bugs] [ maxima-Bugs-3534858 ] Calculus mistake: wrong answer: limit

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Bugs item #3534858, was opened at 2012-06-13 05:32
Message generated for change (Comment added) made by dgildea
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Category: Lisp Core - Limit
Group: To be reviewed
>Status: Closed
>Resolution: Fixed
Priority: 5
Private: No
Submitted By: Chris (chrishalliwell)
Assigned to: Nobody/Anonymous (nobody)
Summary: Calculus mistake: wrong answer: limit

Initial Comment:
Maxima version: 5.27.0

limit((sin(x)-tan(x))/(x*(cos(x)-1)),x,0);
gives 0, but should be 1
and
limit((sin(x)-tan(x))/(x^2*(cos(x)-1)),x,0);
gives 0, but should be infinity (+ at + and - at - inf)

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>Comment By: Dan Gildea (dgildea)
Date: 2012-06-16 05:26

Message:
Fixed in limit.lisp.


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Comment By: Chris (chrishalliwell)
Date: 2012-06-14 04:30

Message:
So is this important to be fixed or we will leave this fot the users to be
careful with trigonometric function limits?
I think that limit should always use trigsimp and all remaining simplify
functions to maximize probability of getting correct value.

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Comment By: Raymond Toy (rtoy)
Date: 2012-06-13 19:27

Message:
limit most likely gets it wrong because it doesn't see that the expression
is the same as sin(x)/cos(x)/x.  (trigsimp produces this.)  Then limit is
correct.

tlimit produces the correct limit.

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