Comment #7 on issue 1690 by ness...@googlemail.com:
integrate(A*x**2*exp(-B*x**2), (x, 0, oo)) gives wrong solution
http://code.google.com/p/sympy/issues/detail?id=1690
For the record, in gsoc-3 this now returns:
In [71]: integrate(z*x**2*exp(-y*x**2), (x, 0, oo))
Out[71]:
⎧ ⎽⎽⎽
⎪ ╲╱ π ⋅z π
⎪───────────────────── for │periodic_argument(y, ∞)│ < ─
⎪ ⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽ 2
⎪4⋅y⋅╲╱ polar_lift(y)
⎪
⎨ ∞
⎪ ⌠
⎪ ⎮ 2
⎪ ⎮ 2 -x ⋅y
⎪ ⎮ x ⋅z⋅ℯ dx otherwise
⎪ ⌡
⎩ 0
Which is as correct as it gets (I think), although it could come out nicer.
(The condition can be written as Re(y) > 0, and sqrt(polar_lift(y)) means
the same thing as sqrt(y) here.)
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