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In "Surely You're Joking, Mr. Feynman!," Nobel-prize winning Physicist Richard Feynman said that he challenged his colleagues to give him an integral that they could evaluate with only complex methods that he could not do with real methods:

One time I boasted, "I can do by other methods any integral anybody else needs contour integration to do."

So Paul [Olum] puts up this tremendous damn integral he had obtained by starting out with a complex function that he knew the answer to, taking out the real part of it and leaving only the complex part. He had unwrapped it so it was only possible by contour integration! He was always deflating me like that. He was a very smart fellow.

Does anyone happen to know what this integral was?

  • 44
    Strange, shouldn't it say "imaginary part" instead of "complex part"?2012-12-09
  • 15
    Although finding that specific integral may be hopeless, perhaps we can make one ourselves? Feynman was indeed a genius, but seeing how we would solve integrals involving branch cuts and such without use of any contour integration is interesting. You need not learn higher level of integration or of mathematics to do it; such is the meaning and application of counter integration.2012-12-12
  • 4
    Is this different from question 167304?2013-01-18
  • 9
    @downvoter: Why?2013-01-19
  • 37
    Check this out: http://ocw.mit.edu/courses/mathematics/18-304-undergraduate-seminar-in-discrete-mathematics-spring-2006/projects/integratnfeynman.pdf2013-01-23
  • 1
    Thanks for posting the PDF, although it's kept me up tonight as I couldn't stop reading :)2013-03-21
  • 2
    Also see http://lesswrong.com/lw/cvf/where_fermi_fails_what_is_hard_to_estimate/2013-05-12

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