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need help with this double integral question :)
http://gyazo.com/a3e6e7133a02d92949f4a14f0cb3961e
 10 months ago
 10 months ago
need help with this double integral question :) http://gyazo.com/a3e6e7133a02d92949f4a14f0cb3961e
 10 months ago
 10 months ago

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FutureMathProfessorBest ResponseYou've already chosen the best response.1
What are you stuck with?
 10 months ago

FutureMathProfessorBest ResponseYou've already chosen the best response.1
\[\int\limits_{\pi}^{2\pi}\int\limits_{0}^{1}xsin(xy)dxdy\]
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
since your limits are constants; you can prolly more easily swap it for dydx
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
which proff did ... ironically :)
 10 months ago

FutureMathProfessorBest ResponseYou've already chosen the best response.1
IRONICALLY?!?! LOOOOOOOOOOL
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
\[\int\limits_{\pi}^{2\pi}\int\limits_{0}^{1}xsin(xy)~dydx\] \[\int\limits_{\pi}^{2\pi}\left(\int\limits_{0}^{1}xsin(xy)~dy\right)dx\]
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
doh ... loathesome integrals!!
 10 months ago

FutureMathProfessorBest ResponseYou've already chosen the best response.1
@amistre64 doesn't the zero to one have to stick with the dx differential though?
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
\[\int_{x=0}^{x=1}\left(\int_{y=\pi}^{y=2\pi}xsin(xy)~dy\right)dx\]
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
it tends to help me out if i label the integrals ....
 10 months ago

FutureMathProfessorBest ResponseYou've already chosen the best response.1
Isn't the general integral of that xsin(xy)/y
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
\[\int_{x=0}^{x=1}\left(\int_{y=\pi}^{y=2\pi}xsin(xy)~dy\right)dx\] \[\int_{x=0}^{x=1}cos(2\pi~x)+cos(\pi~x)~dx\]
 10 months ago

FutureMathProfessorBest ResponseYou've already chosen the best response.1
I thought you didn't have to do parts integration since your X term out front evidently doesn't have a Y in it?
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
you still have to integrate your limits respectively x = [0,1] has to address your dx y = [pi, 2pi] has to address your dy
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
the dx, dy parts tells you what you focus on while leaving the other term a constant
 10 months ago

FutureMathProfessorBest ResponseYou've already chosen the best response.1
LOLOL I forgot about that
 10 months ago

FutureMathProfessorBest ResponseYou've already chosen the best response.1
I didn't realize you were evaluating limits in your 2nd step of that response
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
let x = k int k sin(ky) dy > cos(ky) cos(x 2pi)  cos(x pi)
 10 months ago

amistre64Best ResponseYou've already chosen the best response.3
int cos(x pi)  cos(x 2pi) dx sin(x pi)/pi  sin(x 2pi)/2pi (sin(pi)/pi  sin(2pi)/2pi)  (sin(0 pi)/pi  sin(0 2pi)/2pi) (0  0)  (0  0) so with any luck :)
 10 months ago
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