From 967f91512ca4415df4950ae9cc5cd5d524e6edca Mon Sep 17 00:00:00 2001
From: Richard Kreckel
Date: Mon, 13 Mar 2000 17:12:12 +0000
Subject: [PATCH 1/1] - New example in Tour of GiNaC about exact radicals.
---
doc/tutorial/ginac.texi | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/doc/tutorial/ginac.texi b/doc/tutorial/ginac.texi
index d4ab7fb5..a47e7cad 100644
--- a/doc/tutorial/ginac.texi
+++ b/doc/tutorial/ginac.texi
@@ -280,8 +280,23 @@ integers:
1/3
@end example
-All numbers occuring in GiNaC's expressions can be converted into floating
-point numbers with the @code{evalf} method, to arbitrary accuracy:
+Exact numbers are always retained as exact numbers and only evaluated as
+floating point numbers if requested. For instance, with numeric
+radicals is dealt pretty much as with symbols. Products of sums of them
+can be expanded:
+
+@example
+> expand((1+a^(1/5)-a^(2/5))^3);
+1+3*a+3*a^(1/5)-5*a^(3/5)-a^(6/5)
+> expand((1+3^(1/5)-3^(2/5))^3);
+10-5*3^(3/5)
+> evalf((1+3^(1/5)-3^(2/5))^3);
+0.33408977534118624238
+@end example
+
+The function @code{evalf} that was used above converts any number in
+GiNaC's expressions into floating point numbers. This can be done to
+arbitrary predefined accuracy:
@example
> evalf(1/7);
--
2.25.4