Status: Valid
Owner: ----
Labels: Type-Defect Priority-Medium Integration
New issue 3365 by [email protected]: Integration of x**n*exp(-x**2)
http://code.google.com/p/sympy/issues/detail?id=3365
The integration of x**n*exp(-x**2) returns an invalid (really??) result:
In [20]: integrate(x**n*exp(-x**2), x, meijerg=True)
Out[20]: n*gamma(n/2 + 1/2)*lowergamma(n/2 + 1/2, x**2)/(4*gamma(n/2 +
3/2)) + gamma(n/2 + 1/2)*lowergamma(n/2 + 1/2, x**2)/(4*gamma(n/2 + 3/2))
In [21]: _.subs(n,1)
Out[21]: 1/2 - exp(-x**2)/2
But we know that:
In [22]: integrate(x*exp(-x**2), x)
Out[22]: -exp(-x**2)/2
One should interpret this additional 1/2 as the constant of integration.
However it seems a little bit missleading that the two approaches return
different results.
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