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Solution of x^y=y^x

  1. Jun 29, 2010 #1
    We know that the solutions of x^y=y^x are (2,4) and (4,2), but please tell me how to solve it. I have tried to take log wrt x on both side.
  2. jcsd
  3. Jun 29, 2010 #2


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  4. Jun 30, 2010 #3


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    This is only the case for when restricted to x=2 or y=4. Another example would be (3,3) and (4.4) - of course this could be generalised to all y=x with certain restrictions.

    But this isn't the only set of solutions, Taking (3,y) we can have y=3 and also [itex]y\approx 2.478[/itex].
    And if you take a look at the thread arildno posted, you'll see there are complex solutions as well.
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