Aha! Thanks for the explanation. On Apr 10, 2007, at 9:23 PM, William Stein wrote:
> On 4/10/07, Yi Qiang <[EMAIL PROTECTED]> wrote: >> sage: QQ >> Rational Field >> sage: sqrt(2) in QQ >> True >> >> This looks awfully wrong to me. > > This is correct, because sqrt(2) is a floating point approx. When > sqrt is > replaced by a symbolic function "sqrt", which will happen in the > not-to-distant > future, then sqrt(2) will be an exact object, and it won't be in > QQ. But all > floats are in QQ. Also, note that "a in X" means "a is equal to some > elements of X". > > sage: a = sqrt(2) > sage: a > 1.41421356237310 > sage: b = QQ(a) > sage: b > 4058818056/2870017771 > sage: a == b > True > > William Cheers, Yi -- http://www.yiqiang.net --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
