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Homework Help: Double integration with cos x^2

  1. Nov 4, 2007 #1
    ok so I have the problem ycos(x^2)dxdy with parameters dx=y^2 to 1 and dx=0 to 1
    the first problem I have is integrating cos with respect to x^2. is it a double angle identity? the second is how do I go further if Y^2 gets added into the mix later?
    The attempts I have made have made me even more confused than before. I looked up how I could integrate cos x^2 and could not find a clear answer.
    Help is appreciated.
     
  2. jcsd
  3. Nov 4, 2007 #2

    Galileo

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    Did you copy the limits of integration correctly?
    Should it be x going from y^2 to 1 and then y going from 0 to 1?
     
  4. Nov 4, 2007 #3
    What is the identity of cosx^2? if you don't know then look it up in your book.
     
  5. Nov 5, 2007 #4

    Gib Z

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    It can't be expressed in terms of elementary functions, look up the Cosine Fresnel integral for the solution.
     
  6. Nov 5, 2007 #5

    Galileo

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    Not so fast.
    Try reparametrizing your region of integration. If you first integrate wrt y, then wrt x you may find a solution. (Hint: You will).
     
  7. Nov 5, 2007 #6

    Gib Z

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    O sorry I should have read the whole question, Mainly just read post 3 and replied to that.
     
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