calc-alg.el (math-simplify-divide): Don't cross multiply

in an equation when the lhs is a variable.

2 files changed, 9 insertions, 1 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 9377f334bd4..7f612cb61a4 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2012-07-25  Jay Belanger  <jay.p.belanger@gmail.com>
+
+        * calc-alg.el (math-simplify-divide): Don't cross multiply
+        in an equation when the lhs is a variable.
+
 2012-07-24  Julien Danjou  <julien@danjou.info>
 
         * net/netrc.el (netrc-find-service-number, netrc-store-data):
diff --git a/lisp/calc/calc-alg.el b/lisp/calc/calc-alg.el
index 8e41b175321..50b31400a6a 100644
--- a/lisp/calc/calc-alg.el
+++ b/lisp/calc/calc-alg.el
@@ -530,7 +530,10 @@
                            (not (Math-realp (nth 1 math-simplify-expr))))
                        (math-common-constant-factor (nth 1 math-simplify-expr))))
           (if (and (eq (car-safe nn) 'frac) (eq (nth 1 nn) 1) (not n))
-              (progn
+              (unless (and (eq (car-safe math-simplify-expr) 'calcFunc-eq)
+                           (eq (car-safe (nth 1 math-simplify-expr)) 'var)
+                           (not (math-expr-contains (nth 2 math-simplify-expr) 
+                                                    (nth 1 math-simplify-expr))))
                 (setcar (cdr math-simplify-expr)
                         (math-mul (nth 2 nn) (nth 1 math-simplify-expr)))
                 (setcar (cdr (cdr math-simplify-expr))