Struggling with Complex Double Integrals

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The discussion centers on the difficulty of solving a complex double integral, specifically ∫∫(x^2 + xy + 1) dy dx, with specified bounds. Users share their attempts at simplifying the inner integral, which leads to complicated expressions that are challenging to reduce. One participant mentions obtaining a specific result but struggles with further simplification. Suggestions include using substitution techniques and checking results with online integral calculators like Wolfram Alpha. The conversation highlights the common challenges faced when dealing with intricate integrals in calculus.
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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.
 
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Blast0 said:
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
 
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 couldn't reach a solution.
 
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