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`int` `int` `dxdy/sqrt(x^2+y^2+z^2)` this is the found in my text. this is definite...

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scikm | eNotes Newbie

Posted October 28, 2013 at 7:18 AM via web

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`int` `int` `dxdy/sqrt(x^2+y^2+z^2)`

this is the found in my text. this is definite integral, both starting with -a/2 to a/2. but i need the way if it is indefinite?

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sciencesolve | Teacher | (Level 3) Educator Emeritus

Posted October 28, 2013 at 1:44 PM (Answer #1)

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Usually, when you need to evaluate a double integral over a region, the integrand  is a function f(x,y). You need to notice that the integrand provided by the problem contains the variable z, 1/(x^2 + y^2 + z^2), hence, under the given conditions, you cannot evaluate the given definite integral.

Supposing that you need to evaluate the following double integral over the rectangular region [-a/2,a/2] yields:

int_(-a/2)^(a/2) int_(-a/2)^(a/2) 1/(sqrt(x^2 + y^2))dxdy

Since the order of integration does not matter, either you willl start to integrate with respect to y, or you will start to integrate with respect to x, the results will coincide.

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