Issue 3288: document as_integer_ratio(), fromhex(), and hex().
diff --git a/Doc/tutorial/floatingpoint.rst b/Doc/tutorial/floatingpoint.rst
index c9408c9..8816acc 100644
--- a/Doc/tutorial/floatingpoint.rst
+++ b/Doc/tutorial/floatingpoint.rst
@@ -138,7 +138,39 @@
If you are a heavy user of floating point operations you should take a look
at the Numerical Python package and many other packages for mathematical and
statistical operations supplied by the SciPy project. See <http://scipy.org>.
-
+
+Python provides tools that may help on those rare occasions when you really
+*do* want to know the exact value of a float. The
+:meth:`float.as_integer_ratio` method expresses the value of a float as a
+fraction::
+
+ >>> x = 3.14159
+ >>> x.as_integer_ratio()
+ (3537115888337719L, 1125899906842624L)
+
+Since the ratio is exact, it can be used to losslessly recreate the
+original value::
+
+ >>> x == 3537115888337719 / 1125899906842624
+ True
+
+The :meth:`float.hex` method expresses a float in hexadecimal (base
+16), again giving the exact value stored by your computer::
+
+ >>> x.hex()
+ '0x1.921f9f01b866ep+1'
+
+This precise hexadecimal representation can be used to reconstruct
+the float value exactly::
+
+ >>> x == float.fromhex('0x1.921f9f01b866ep+1')
+ True
+
+Since the representation is exact, it is useful for reliably porting values
+across different versions of Python (platform independence) and exchanging
+data with other languages that support the same format (such as Java and C99).
+
+
.. _tut-fp-error:
Representation Error