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Can someone please check my answer: Trig Substitution problem

  1. Feb 26, 2009 #1
    I tried to use the latex reference but it was way too complicated for me.
    Can you see the attachment.
    Thank you!
     

    Attached Files:

  2. jcsd
  3. Feb 26, 2009 #2

    HallsofIvy

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    Staff Emeritus
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    If you are letting [itex]x= cos(\theta)[/itex] then [itex]dx= cos(\theta)d\theta[/itex]. It looks to me like you forgot that [itex]cos(\theta)[/itex].
     
  4. Feb 26, 2009 #3
    Thank you HallsofIvy for your help.
    Yes it did forget! but wouldn't by dx= sin [tex]\vartheta[/tex]
    please see the updted the attachment.
     

    Attached Files:

  5. Feb 26, 2009 #4

    Mark44

    Staff: Mentor

    If x = cos([itex]\theta[/itex]), then dx = -sin([itex]\theta[/itex])d[itex]\theta[/itex]
     
  6. Feb 26, 2009 #5

    HallsofIvy

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    Yes, of course Mark44 is right. I don't know what came over me!
     
  7. Feb 26, 2009 #6
    Thanks Mark44! that negative sign is sure important...:redface:
     
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