--- math.rst.original	2008-07-24 16:35:59.000000000 +0300
+++ math.rst	2008-07-24 23:11:41.000000000 +0300
@@ -255,6 +255,30 @@
    Return the hyperbolic tangent of *x*.
 
+Error functions:
 
 
+.. function:: erf(x)
+
+   Return the error function of *x*.
+
+
+.. function:: erfc(x)
+
+   Return the complementary error function of *x*.
+
+Gamma functions:
+
+
+.. function:: lgamma(x)
+
+   Return the natural logarithm of gamma function of *x*.
+   Raises :exc:`ValueError` if *x* is negative integer or zero.
+
+
+.. function:: tgamma(x)
+
+   Return the gamma function of *x*.
+   Raises :exc:`ValueError` if *x* is negative integer or zero.
+
 The module also defines two mathematical constants: