On Sun, Mar 4, 2012 at 10:39 AM, prateek papriwal <papriwalprat...@gmail.com
> wrote:
> so somehow we need to merge nsimplify() method into sqrt() method .
>
> in that case when we call sqrt(4.41)
>
> automatically sqrt(nsimplify(4.41,rational=True)) will be called .
>
>
>
Since 4.41 is a Float, we don't assume that it is an exact number so the
conversion happens (as Aaron is noted) upon instantiation of the sqrt and
2.1 is returned. If you know the 4.41 is exact you can enter it as a string
to Rational:
>>> sqrt(Rational('4.41'))
21/10
Also, it seems the following could be added to Pow:
def _eval_is_rational(self):
p = self.func(*self.as_base_exp()) # in case it's unevaluated
if not p.is_Pow:
return p.is_rational
b, e = p.as_base_exp()
if e.is_Rational and not e.is_Integer and b.is_Rational:
return False
This would allow False to be returned for sqrt(3).is_rational (or True for
is_irrational).
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