Boole does not work with symbolic limits in Integrate ?
- To: mathgroup at smc.vnet.net
- Subject: [mg73102] Boole does not work with symbolic limits in Integrate ?
- From: Mitch Murphy <mitch at mix5.com>
- Date: Sat, 3 Feb 2007 04:16:07 -0500 (EST)
hey hey
use of the boole indicator function inside integrate only works for
numerical arguments, symbolic limits of integration just returns the
unevaluated integral.
simple example ...
Integrate[2 u Boole[a < u], {u, 0, x}]
out[] = Integrate[2 u Boole[a < u], {u, 0, x}]
i would expect ...
Integrate[2 u , {u, a, x}]
out[] = x^2 - a^2
but it does work with numerical limits of integration ...
Integrate[2 u Boole[a < u], {u, 0, 2}]
out[] = Piecewise[{{4, a <= 0}, {4 - a^2, 0 < a < 2 }]
anybody know a trick to make this work ? i've tried a bunch of
variations using evaluate[], logicalexpand[], piecewiseexpand[],
assumptions->x Reals, ..., but nothing works.
cheers,
Mitch