[Maxima-commits] Maxima, A Computer Algebra System branch master updated. branch-5_27-base-135-gd728509

[Dan G. <dg...@us...>]

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- Log -----------------------------------------------------------------
commit d7285090062776ab70033ec444a5d608f3965522
Author: Dan Gildea <dgildea>
Date:   Sat Jun 16 08:23:54 2012 -0400

    Fix Calculus mistake: wrong answer: limit - ID: 3534858
    
    src/limit.lisp:
    o lhsimp: use ridofab to handle case (zeroa + zerob)
    
    tests/retest16.mac
    o add limit((sin(x)-tan(x))/(x*(cos(x)-1)),x,0);

diff --git a/src/limit.lisp b/src/limit.lisp
index f5bf22f..4bf4ced 100644
--- a/src/limit.lisp
+++ b/src/limit.lisp
@@ -1491,12 +1491,13 @@ It appears in LIMIT and DEFINT.......")
 		 (t (setq varl (m* (car l) varl))))))
 	(t (cons 1 expr))))
 
+;; if term goes to non-zero constant, replace with constant
 (defun lhsimp (term var val)
   (cond ((atom term)  term)
 	(t
-	 (let ((term-value (limit term var val 'think)))
+	 (let ((term-value (ridofab (limit term var val 'think))))
 	   (cond ((not (member term-value
-			       '($inf $minf $und $ind $infinity $zeroa $zerob 0)))
+			       '($inf $minf $und $ind $infinity 0)))
 		  term-value)
 		 (t term))))))
 
diff --git a/tests/rtest16.mac b/tests/rtest16.mac
index cd9d3af..63527a7 100644
--- a/tests/rtest16.mac
+++ b/tests/rtest16.mac
@@ -490,6 +490,10 @@ limit(x*expintegral_ei(x), x, 0);
 limit(factorial(x),x,-2,plus);
 minf;
 
+/* Calculus mistake: wrong answer: limit - ID: 3534858 */
+limit((sin(x)-tan(x))/(x*(cos(x)-1)),x,0);
+1;
+
 limit(1/psi[1](x), x, inf);
 inf;
 

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

Summary of changes:
 src/limit.lisp    |    5 +++--
 tests/rtest16.mac |    4 ++++
 2 files changed, 7 insertions(+), 2 deletions(-)


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