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Math Help - What exactly is this question asking?

  1. #1
    Newbie
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    Melbourne, Australia
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    What exactly is this question asking?

    I'm not too sure if I'm approaching the question correctly:

    (a) Find \frac {d}{dx} [\frac {-1}{\sqrt{1+x^2}}](b) Hence evaluate \\ \int_0^2 {\frac{x}{(1+x^2)^\frac{3}{2}}}dx

    And this is my attempt:

    (a)
    Find \frac {d}{dx} [\frac {-1}{\sqrt{1+x^2}}]

    = \frac{2x}{2(x^2 +1)^\frac{3}{2}}
    (b) Hence evaluate \int_0^2 {\frac{x}{(1+x^2)^\frac{3}{2}}}dx

    =-\frac {1}{\sqrt{x^2 +1}}\\\\for 2\\=-\frac {1}{\sqrt{5}}\\\\for 0\\\\=-1\\\\=-\frac {1}{\sqrt{5}}-(-1)\\\\= 1-\frac {1}{\sqrt{5}} \approx 0.553

    Help much appreciated!
    Last edited by moob; May 13th 2013 at 12:30 AM.
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  2. #2
    Super Member
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    Re: What exactly is this question asking?

    you are very right. In a way he has given the integral you just have to evaluate between the interval for the given interval.
    Thanks from moob
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