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Thread: 2 integration method giving different results? Where did I go wrong?

  1. April 22nd 2010, 05:54 PM #1
    chengbin
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    2 integration method giving different results? Where did I go wrong?

    \int 2(x+1)dx

    Method 1

    u=x+1
    du=dx
    \int 2udu
    u^2+c
    (x+1)^2+c

    Method 2

    \int (2x+2) dx
    x^2+2x+c

    ???
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  2. April 22nd 2010, 05:59 PM #2
    skeeter
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    Quote Originally Posted by chengbin View Post
    \int 2(x+1)dx

    Method 1

    u=x+1
    du=dx
    \int 2udu
    u^2+c
    (x+1)^2+c

    Method 2

    \int (2x+2) dx
    x^2+2x+c

    ???
    both are correct ... they only differ by a constant.
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