Integrate: A feature or a bug?
- To: mathgroup at smc.vnet.net
- Subject: [mg34248] Integrate: A feature or a bug?
- From: Vladimir Bondarenko <vvb at mail.strace.net>
- Date: Sun, 12 May 2002 03:25:44 -0400 (EDT)
- Reply-to: Vladimir Bondarenko <vvb at mail.strace.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hello,
I have a fairly old version of Mathematica.
It produces
In[1] := Integrate[Integrate[Integrate[Integrate[1/(4 - (x + y + z + w)),
{x, 1, 2}], {y, 1, 2}], {z, 1, 2}], {w, 1, 2}]
Out[1] = Integrate[Integrate[Integrate[If[w + y + z < 2 || Im[w + y + z] != 0 ||
w + y + z > 4 && w + y + z > 4, Log[(-3 + w + y + z)/(-4 + w + y + z)] -
Log[(-2 + w + y + z)/(-4 + w + y + z)], Integrate[(4 - w - x - y - z)^(-1), {x, 1, 2},
Assumptions -> Im[w + y + z] == 0 && w + y + z >= 2 && w + y + z <= 4]], {y, 1, 2}],
{z, 1, 2}], {w, 1, 2}]
Is is a feature or a bug?
Can anybody interpret the output?
My idea, the answer is
((-176*Log[2])/3 + 36*Log[3])/2
-0.557296
New version 4.1 produces
NIntegrate[Integrate[Integrate[Integrate[1/(4 - (x + y + z + w)),
{x, 1, 2}], {y, 1, 2}], {z, 1, 2}], {w, 1, 2}]
-0.557296
Thank you in advance.
Vladimir Bondarenko