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Math Help - infinite limits

  1. #1
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    problem is attached, i got as far as (√x)(√(x+1)-√(x-1)).
    Attached Thumbnails Attached Thumbnails infinite limits-screen-shot-2009-09-30-5.50.27-pm.png  
    Last edited by mr fantastic; September 30th 2009 at 10:25 PM. Reason: Merged posts
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  2. #2
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    {\sqrt{x^2+x} - \sqrt{x^2-x}} \cdot \frac{\sqrt{x^2+x} + \sqrt{x^2-x}}{\sqrt{x^2+x} + \sqrt{x^2-x}} =

    \frac{(x^2+x) - (x^2-x)}{\sqrt{x^2+x} + \sqrt{x^2-x}}=

    \frac{2x}{\sqrt{x^2+x} + \sqrt{x^2-x}} =

    divide numerator by x , denominator by \sqrt{x^2} ... ( note: since x > 0 , x = \sqrt{x^2} )

    \frac{2}{\sqrt{1+\frac{1}{x}} + \sqrt{1- \frac{1}{x}}}

    now take the limit as x \to \infty
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  3. #3
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    Oh yeeeeaaah, multiplying by the conjugaaaaate. should've thought that one out a little better. thanks a lot!
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