merges r28698 from trunk into ruby_1_9_2.

--
* lib/cmath.rb (CMath#cbrt): cbrt should accept a negative real
  numbers.  [ruby-core:31234]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@28718 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/cmath.rb b/lib/cmath.rb
index b23dac239c..976f269299 100644
--- a/lib/cmath.rb
+++ b/lib/cmath.rb
@@ -85,7 +85,7 @@ module CMath
   end
 
   def cbrt(z)
-    if z.real? and z >= 0
+    if z.real?
       cbrt!(z)
     else
       Complex(z) ** (1.0/3)