I must solve the double integral - ∫ ∫ (x^2 + y^2) e^(-x^4 - 2(x^2)(y^2) - y^4) dy dx Both integrals between infinity and - infinity! Please help!
Last edited by amywilliams99; Mar 15th 2010 at 10:59 AM.
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Sorry, error
Last edited by tom@ballooncalculus; Mar 15th 2010 at 10:52 AM.
Some one please help! I have attempted to use x = rcos(theta) and y=rsin(theta) but cant seem to get an answer.
Hi. How about using polar coordinates? You know $\displaystyle x^2+y^2=r^2$ right? Then turn the crank: $\displaystyle \int_{-\infty}^{\infty}\int_{-\infty}^{\infty} (x^2+y^2)e^{-(x^2+y^2)^2} dydx=\int_0^{2\pi}\int_0^{\infty}r^2 e^{-r^4}rdrdt$
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