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Homework Help: Cosh and sinh identity

  1. Mar 2, 2014 #1
    Is it true that:

    exp(2x)sinh(y)2 + exp(-2x) = exp(2x)cosh(y)2-2sinh(2x)

    I need this to be correct for an exercise but I don't know how to show it. I tried using something like cosh2+sinh2=1, but it didn't work.
     
  2. jcsd
  3. Mar 2, 2014 #2
    Perhaps use the definition of sinh and cosh to express everything as exponentials?
     
  4. Mar 2, 2014 #3

    epenguin

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    In general cosh2+sinh2 ≠1 :wink:
     
  5. Mar 2, 2014 #4

    Dick

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    It might also help if you use the correct relation. cosh^2-sinh^2=1.
     
  6. Mar 2, 2014 #5

    epenguin

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    I thought ;) would propel him there. ;)
     
  7. Mar 2, 2014 #6

    Dick

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    Yeah, I didn't see your hint until after I posted. Sorry.
     
  8. Mar 2, 2014 #7

    epenguin

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    No matter. :smile:
     
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