diff --git a/ChangeLog b/ChangeLog
index 08a524dd54..fe3868afd2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sun Aug 31 20:49:42 2008  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* complex.c (numeric_abs2): new.
+
 Sun Aug 31 18:22:04 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/mkmf.rb (have_devel?): checks if the compiler works.
diff --git a/complex.c b/complex.c
index 39e8ad2f85..34255df9fd 100644
--- a/complex.c
+++ b/complex.c
@@ -1291,6 +1291,12 @@ numeric_image(VALUE self)
     return INT2FIX(0);
 }
 
+static VALUE
+numeric_abs2(VALUE self)
+{
+    return f_mul(self, self);
+}
+
 #define id_PI rb_intern("PI")
 
 static VALUE
@@ -1473,6 +1479,7 @@ Init_Complex(void)
     rb_define_method(rb_cNumeric, "real", numeric_real, 0);
     rb_define_method(rb_cNumeric, "image", numeric_image, 0);
     rb_define_method(rb_cNumeric, "imag", numeric_image, 0);
+    rb_define_method(rb_cNumeric, "abs2", numeric_abs2, 0);
     rb_define_method(rb_cNumeric, "arg", numeric_arg, 0);
     rb_define_method(rb_cNumeric, "angle", numeric_arg, 0);
     rb_define_method(rb_cNumeric, "phase", numeric_arg, 0);
diff --git a/test/ruby/test_complex.rb b/test/ruby/test_complex.rb
index 145306ed2a..b797ec10d0 100644
--- a/test/ruby/test_complex.rb
+++ b/test/ruby/test_complex.rb
@@ -856,6 +856,11 @@ class Complex_Test < Test::Unit::TestCase
     assert_equal(1, 1.0.magnitude)
     assert_equal(1, -1.0.magnitude)
 
+    assert_equal(4, 2.abs2)
+    assert_equal(4, -2.abs2)
+    assert_equal(4.0, 2.0.abs2)
+    assert_equal(4.0, -2.0.abs2)
+
     assert_equal(0, 1.arg)
     assert_equal(0, 1.angle)
     assert_equal(0, 1.phase)
diff --git a/test/ruby/test_rational.rb b/test/ruby/test_rational.rb
index ece44a9051..c5855a0345 100644
--- a/test/ruby/test_rational.rb
+++ b/test/ruby/test_rational.rb
@@ -953,6 +953,10 @@ class Rational_Test < Test::Unit::TestCase
     assert_equal(Rational(9,1), Rational(1,9).reciprocal)
     assert_equal(Rational(-1,9), Rational(-9,1).reciprocal)
     assert_equal(Rational(-9,1), Rational(-1,9).reciprocal)
+    assert_equal(Rational(1,9), Rational(9,1).inverse)
+    assert_equal(Rational(9,1), Rational(1,9).inverse)
+    assert_equal(Rational(-1,9), Rational(-9,1).inverse)
+    assert_equal(Rational(-9,1), Rational(-1,9).inverse)
   end
 =end
 
@@ -1047,9 +1051,9 @@ class Rational_Test < Test::Unit::TestCase
 
 =begin
     assert_equal(Rational(1,9), 9.reciprocal)
-    assert_equal(Rational(1,9), 9.0.reciprocal)
+    assert_in_delta(0.1111, 9.0.reciprocal, 0.001)
     assert_equal(Rational(1,9), 9.inverse)
-    assert_equal(Rational(1,9), 9.0.inverse)
+    assert_in_delta(0.1111, 9.0.inverse, 0.001)
 =end
 
     assert_equal(Rational(1,2), 1.quo(2))