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Math Help - simple rearrangement which i cant do!

  1. #1
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    simple rearrangement which i cant do!

    how is this: (4+x^2)/sqrt(4+x^2)
    the same as sqrt(4+x^2)
    ?? could someone explain step by step? thanks
    Last edited by situation; December 2nd 2010 at 11:28 AM. Reason: fixing equation
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  2. #2
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    Quote Originally Posted by situation View Post
    how is this: (4+x^2)/sqrt(4+x^2)
    the same as 4+x^2
    ?? could someone explain step by step? thanks
    Hint: for positive a\in\mathbb{R}\,,\,\,\frac{a}{\sqrt{a}}=\sqrt{a} . Prove it!

    Tonio

    Ps. By the way, your quiestion is incorrect, of course.
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  3. #3
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    e^(i*pi)'s Avatar
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    If you let u = \sqrt{4+x^2} then you get \dfrac{u^2}{u} which is u.

    Alternatively, recall that a = \sqrt{|a|}\sqrt{|a|}
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  4. #4
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    Quote Originally Posted by situation View Post
    how is this: (4+x^2)/sqrt(4+x^2)
    the same as 4+x^2
    ?? could someone explain step by step? thanks
    do you mean \dfrac{4+x^2}{\sqrt{4+x^2}}=4+x^2??

    That is not true...

    Actually \dfrac{4+x^2}{\sqrt{4+x^2}}=\sqrt{4+x^2}
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    Quote Originally Posted by e^(i*pi) View Post
    If you let u = \sqrt{4+x^2} then you get \dfrac{u^2}{u} which is u.

    Alternatively, recall that a = \sqrt{|a|}\sqrt{|a|}

    god i feel stupid now! thank you
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  6. #6
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    Quote Originally Posted by harish21 View Post
    do you mean \dfrac{4+x^2}{\sqrt{4+x^2}}=4+x^2??

    That is not true...

    Actually \dfrac{4+x^2}{\sqrt{4+x^2}}=\sqrt{4+x^2}
    that is what i meant sorry just couldnt see it!
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