[Maxima-commits] CVS: maxima-pre59/src limit.lisp,1.3,1.4

[Raymond T. <rt...@us...>]

Update of /cvsroot/maxima/maxima-pre59/src
In directory usw-pr-cvs1:/tmp/cvs-serv1234/src

Modified Files:
	limit.lisp 
Log Message:
Replacement for the limit of tan functions.  Use definition tan=sin/cos
instead of complicated code.


Index: limit.lisp
===================================================================
RCS file: /cvsroot/maxima/maxima-pre59/src/limit.lisp,v
retrieving revision 1.3
retrieving revision 1.4
diff -u -d -r1.3 -r1.4
--- limit.lisp	2002/01/09 20:46:37	1.3
+++ limit.lisp	2002/01/22 02:31:13	1.4
@@ -2491,6 +2491,7 @@
 			(SIMPLIFY (LIST (NCONS FN) (RIDOFAB ARG)))
 			FN))))
 
+#+nil
 (DEFUN SIMPLIM%TAN (ARG) 
    (let ((arg1 (ridofab (limit arg var val 'think))))
      (COND
@@ -2519,6 +2520,14 @@
 	     ((equal arg1 -1) '$zerob)
 	     (t 0)))
       (t (SIMP-%TAN (LIST '(%TAN) ARG1) 1. NIL)))))
+
+;; Instead of the complicated implementation above, why not use the
+;; fact that tan = sin/cos?  Takes care of the bug that
+;; limit(tan(x+%pi/4),x,0) doesn't return 1.
+(defun simplim%tan (arg)
+  (simplimit `((mtimes simp) ((%sin simp) ,arg)
+	       ((mexpt simp) ((%cos simp) ,arg) -1))
+	     var val))
 
 (DEFUN SIMPLIM%ASINH (ARG) 
        (COND ((MEMQ ARG '($INF $MINF $ZEROA $ZEROB $IND $UND))