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Math Help - definite integral

  1. #1
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    definite integral

    Evaluate the definite integral.




    I really am not sure how to evaluate this integral.

    Do i use the substitution method and set my u = 1+2x?
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  2. #2
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    Try x=\frac{u^2}2 -\frac1{\color{red}2}.

    edit: whoops. Thanks Linnus.
    Last edited by maddas; May 2nd 2010 at 02:48 PM.
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  3. #3
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    [quote=maddas;505552]Try [tex]x=\frac{u^2}2 -1

    how did you get that x value?
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  4. #4
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    Wouldn't it be
    <br />
u= \sqrt{1+2x}<br />
    <br />
u^2=1+2x<br />
    <br />
u^2-1=2x<br />
    <br />
x= (u^2-1)/2<br />
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  5. #5
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    [QUOTE=rhcp1231;505555]
    Quote Originally Posted by maddas View Post
    Try [tex]x=\frac{u^2}2 -1

    how did you get that x value?
    I chose it so that the square root on the bottom would disappear, ie I wanted 1+2x = u^2. But like Linnus pointed out, I lost the 1/2. heh.
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