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Homework Help: Find the mistake

  1. Dec 16, 2006 #1

    ddr

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    1. The problem statement, all variables and given/known data

    π^2
    4
    ∫ COS(√x) dx
    0

    2. Relevant equations



    3. The attempt at a solution

    t=√x ; x=t^2 ; dx= 2t

    π
    2
    ∫ COSt · 2t dt = [SINt · 2t ] - ∫ 2SINt dt = π +2
    0

    yes but.. where is the mistake?
    'cause the result is: π/2 - 1

    thanx a lot
     
  2. jcsd
  3. Dec 16, 2006 #2

    cristo

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    Staff Emeritus
    Science Advisor

    I get π +2. What makes you think the answer is π/2 - 1?
     
  4. Dec 16, 2006 #3
    The answer should be [itex]\pi - 2[/itex]. Check the substitutions in the final step.
     
  5. Dec 16, 2006 #4

    ddr

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    Neutrino is right, the result is π - 2, but why does the book report a π/2 - 1 result?
     
  6. Dec 16, 2006 #5
    A typo, perhaps?
     
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