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Blast0
Oct4-04, 03:24 AM
Hi, I've tried to solve this problem over and over and always end up with an enormous second integral that seems to never reduce to simpler terms.

\int\int(x^2+xy+1)dydx

Where the bounds of the inner integral are [x-1,xcos(2(\pi)x)] and the outer integral are [1,0]

Thank you for any help in advance. Any would be great.

Tide
Oct4-04, 04:13 AM
Hi, I've tried to solve this problem over and over and always end up with an enormous second integral that seems to never reduce to simpler terms.

\int\int(x^2+xy+1)dydx

Where the bounds of the inner integral are [x-1,xcos(2(\pi)x)] and the outer integral are [1,0]

Thank you for any help in advance. Any would be great.


I get

-\frac {116 \pi^2 + 153}{192 \pi^2}

The inner integral came out to be

x(x^2+1) \cos {2\pi x} - \frac {x^3 \sin^2 2\pi x}{2} -x^3 + 2x^2-\frac {3x}{2} + 1

Blast0
Oct4-04, 10:18 AM
Thank you Tide.

For the inner integral I get:

x^3\cos^2(2(\pi)x)+(x(\cos^2(2(\pi)x)))/2+x\cos^2(2(\pi)x)-x(x-1)-((x(x-1)^2)/2)-x+1

I can simplify the second half but not the first. Is there some trick like a substitution to going further from this point, because I've tried integrating this and it was a monster... 2 pages and I couldnt reach a solution.

e(ho0n3
Oct4-04, 10:59 AM
Have you ever used the site http://integrals.wolfram.com/ to check your integrals?