Double integral problem (pretty basic)

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The discussion revolves around a double integral problem in a multivariable calculus course that has stumped the poster, Glenn. He attempted to convert the double integral into an iterated integral but struggled with the integration process, particularly with u-substitution and polynomial long division. A suggestion was made to try integrating with respect to y first, which Glenn acknowledged as a key insight. This approach ultimately helped him move forward with the problem. The conversation highlights the challenges of mastering integration techniques in multivariable calculus.
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Good day, all:

We recently hit double/triple integrals in my multivariable calculus course and I have found that my integration abilities are, well, *beyond* rusty ... and so the problem below, which is one of the very first on my current problem set, has me stumped.

Homework Statement



\int\int_{R}\frac{x}{1+xy} dA R = { [0,1]x[0,1] = {(x,y): 0 \leq x \leq1, 0 \leq y \leq1 }

The Attempt at a Solution



My first and nearly only step was to turn this into an iterated integral:

\int^{1}_{0}\int^{1}_{0}\frac{x}{1+xy} dx dy

... and this is where I begin to choke and sputter. I have started to try u-substitution on this with u = 1+xy, but didn't get anything that made sense to me; some hints I have found online seem to indicate that I should be able to perform "polynomial long division" to turn this into a sum or difference of two simpler integrals, but I guess I don't sufficiently understand polynomial long division to carry this out here.

Any hints would be much appreciated. I am considering dropping this course, but I would like to avoid that ... I need some serious integration mojo to be directly infused into my skull asap. :bugeye:

Regards,

Glenn
 
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Did you try integrating with respect to y first?
 
murmillo said:
Did you try integrating with respect to y first?

No. I'll check it out and see what happens. Thank you.

EDIT: That was key, of course. Jeez. ::strikes forehead::
 
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