#12807: Taking the real part of a sum of exponentials with imaginary exponents
gives wrong result
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Reporter: inaki | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-5.0
Component: symbolics | Keywords:
Work issues: | Report Upstream: N/A
Reviewers: | Authors:
Merged in: | Dependencies:
Stopgaps: |
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In sage 4.8 the following computation gives 1/2, while the right result is
-3/2:
{{{
sage: a = exp(i*2*pi/3)
sage: b = exp(i*pi/3)
sage: c = 2*a-b
sage: c.real()
1/2
}}}
Doing the computation numerically gives the right result:
{{{
sage: N(c).real()
-1.50000000000000
}}}
and asking maxima directly also works:
{{{
sage: (c.maxima_methods().rectform()).real()
-3/2
}}}
This is sage 4.8 running on Fedora 16, linux 3.1.0-7.fc16.x86_64 SMP.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/12807>
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