On 7/6/11 6:20 PM, robin hankin wrote:
[apologies if this is a resend]
Hi. I am having difficulty using sage to manipulate square roots.
Consider:
a = 1 + sqrt(2) + sqrt(3)
b= (a^2).expand()
c = sqrt(b)
Then 'y' should be equal to 'a'.
I get:
sage: a = 1 + sqrt(2) + sqrt(3)
sage: b= (a^2).expand()
sage: c = sqrt(b)
sage: y
---------------------------------------------------------------------------
NameError Traceback (most recent call last)
/Volumes/Private/pass/<ipython console> in <module>()
NameError: name 'y' is not defined
You haven't said what y is.
However, assuming that you really mean c instead of y, here is one way:
sage: QQbar(a)==QQbar(c)
True
You're in luck since these numbers are roots of rational polynomials,
and we have other tools like QQbar to deal with roots of rational
polynomials.
Thanks,
Jason
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