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wrong result when computing a definite integral
Posted:
Jan 10, 2013 9:38 PM


hi group,
i run into this problem today when giving a bunch of easy integrals to mathematica. here's a wolfram alpha link to the problem: http://www.wolframalpha.com/input/?i=Integrate%5BExp%5BI+Sqrt%5B3%5Dy%5D%2C%7Bx%2C2Pi%2C2Pi%7D%2C%7By%2CPi%2CPi%7D%5D#
the integrand does not depend on the 'x' variable, the inner integration should only result in a factor of 4Pi, and the correct result is a real number, yet the below integral gives a complex number which is far off from the correct value: Integrate[Exp[I Sqrt[3] y], {x, 2 Pi, 2 Pi}, {y, Pi, Pi}] > ((4 I (1 + E^(2 I Sqrt[3] Pi)) Pi)/Sqrt[3])
from some trial and error it seems the result is also incorrect for noninteger factors in the exponential.



