# integration from plus to minus infinity

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• Jul 16th 2011, 07:33 AM
transgalactic
integration from plus to minus infinity
it an integral of $\frac{2\pi k' r^3\pho \omega rdr dz}{(z^2+r^2)^\frac{3}{2}}$
its a double integral but
how to integrate by dz
from plus to minus infinity
?
• Jul 16th 2011, 11:56 AM
Chris L T521
Re: integration from plus to minus infinity
Quote:

Originally Posted by transgalactic
it an integral of $\frac{2\pi k' r^3\pho \omega rdr dz}{(z^2+r^2)^\frac{3}{2}}$
its a double integral but
how to integrate by dz
from plus to minus infinity
?

We can't help you because the problem is missing an important piece of information (the limits for r). Please post the whole problem.
• Jul 16th 2011, 11:58 AM
Siron
Re: integration from plus to minus infinity
modified.
• Jul 16th 2011, 12:27 PM
Aryth
Re: integration from plus to minus infinity
Quote:

Originally Posted by Chris L T521
We can't help you because the problem is missing an important piece of information (the limits for r). Please post the whole problem.

Could you switch the order of integration on this? If $2\pi k' \omega$ are constant wrt z and r I don't see the difference in integrating wrt z first or wrt r first. If that is the case you could just integrate wrt z and then let the OP use the limits they have wrt r. (I guess either way there would need to be an extra piece of information, whether the above vars are constant wrt r and z or the limits on r).