Use of erf(x); read text file; command to display available functions

Apparently, the package numericalio provides facility for my 2nd
question.
 
Thanks for the answers to my first. erf(5.0) returns a numerical
result.
 
I am still interested in receiving an answer to my 3rd question. How do
you have Maxima list all available functions - i.e. those that are
built-in, those that are loaded from a package, and those I define. The
"functions" command handles the latter only, apparently.
 
Thanks.
 
________________________________

From: Bartlett, Charles S. 
Sent: Monday, August 13, 2007 3:08 PM
To: 'maxima at math.utexas.edu'
Subject: Use of erf(x); read text file; command to display available
functions



	Why doesn't erf(5) produce a numerical result, whereas sin(.3)
or gamma(.2) do?
	 
	I am using Maxima 5.12.0.
	 
	It appears that my version is not finding a definition for erf.
	 
	--------------------
	 
	Can Maxima read a text file containing a column of numbers?
	 
	 
	--------------------
	 
	Is there a function to display available functions - not just
those defined by a user?
	 
	 
	 
	 
	Thanks.