--- loncom/html/adm/help/tex/Formula_Response_Sampling.tex	2006/04/22 20:57:34	1.4
+++ loncom/html/adm/help/tex/Formula_Response_Sampling.tex	2007/01/22 21:49:26	1.5
@@ -2,8 +2,18 @@
 
 As you may know, it is extremely difficult to determine whether a given expression
 is exactly equal to another expression in general. For example, is $\sin 2x=2\sin x\cos x$?
-Symbolically proving it one way or another is impossible in general. Therefore,
-LON-CAPA uses a sampling system. If your answer and the student's answer
+LON-CAPA has two ways of finding out if it is:
+\begin{itemize}
+\item algebraically, using a symbolic algebra system
+\item numerically, using sampling points
+\end{itemize}
+
+You need to determine which way is the safest in a given situation.
+
+If you don't specify sampling points, the symbolic algebra system is used.
+
+If you do specify sampling points, LON-CAPA uses them.
+If your answer and the student's answer
 agree at the sampling points within your given tolerance factor, the student's
 answer will be accepted. If the student's answer does not agree at the sampling points within your given tolerance factor, it will be rejected.