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Homework Help: Integrate [2x sin (x^2) dx]

  1. Dec 29, 2005 #1
    may i know how to integ [2x sin (x^2) dx]??the answer is -cos(x^2)

  2. jcsd
  3. Dec 29, 2005 #2
    use the subsititution u= x^2
  4. Dec 29, 2005 #3
    [tex]\int 2xsin(x^2)dx = \int sin(x^2) dx^2 = -cos(x^2)[/tex]

    The clue is that

    [tex]2xdx = dx^2[/tex]


    edit : which is basically the same as what What has stated :)
  5. Dec 29, 2005 #4
  6. Dec 31, 2005 #5
    Haha, you don't sound to sure on that. Does it make sense?
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