Drexel dragonThe Math ForumDonate to the Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by Drexel University or The Math Forum.

Math Forum » Discussions » sci.math.* » sci.math.symbolic.independent

Topic: There are still no reports in!
Replies: 5   Last Post: Dec 3, 2011 5:47 PM

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]

Posts: 982
Registered: 4/26/08
There are still no reports in!
Posted: Nov 26, 2011 4:47 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply


many things have changed on sci.math.symbolic since two years ago:

The rule-based integrator Rubi developed by Albert Rich came along as
did version 8 of Mathematica; the Wolfram Researchers are rumored to be
working on a new integrator and have stopped posting to the group; all
posts by Albert Rich were deleted from the Google archive while Rubi's
executable rule system morphed into a merely human-readable formula
collection; and the regular Cyber-Tester messages have finally ceased as

I doubt that all of these changes are unrelated.

But one thing hasn't changed: there are still no reports in on Martin's
second elementary double integral, as posted in October 2009:




jxx(x,y,z) := -x*y*(2*(x^2+y^2+z^2)^(3/2) - 2*z^3 - 3*z*(x^2+y^2)) /

jxy(x,y,z) := ((x^2-y^2)*(x^2+y^2+z^2)*((x^2+y^2+z^2)^(1/2) - z) -
z*x^2*(x^2+y^2)) / ((x^2+y^2+z^2)^(3/2)*(x^2+y^2)^2)

Now, what is the simple, elementary result of:

int(int(jxx(x, y-a/2, z) * jxx(x, y+a/2, z) + jxy(x, y-a/2, z) *
jxy(x, y+a/2, z), x, -inf, inf), y, -inf, inf)

where z >= 0? Simple transformations leading to the solution of a
related problem via elementary antiderivates were shown in



Perhaps somebody wants to give the second double integral another try.
Is your CAS no weakling anymore?


Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© Drexel University 1994-2014. All Rights Reserved.
The Math Forum is a research and educational enterprise of the Drexel University School of Education.