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Math Help - Inverse Function

  1. #1
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    Inverse Function

    How do I find the Inverse of this function?

    Let f(x) = x^2 - 1 for x\geq2. Find f^-1(x)
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  2. #2
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    Quote Originally Posted by SHiFT View Post
    How do I find the Inverse of this function?

    Let f(x) = x^2 - 1 for x\geq2. Find f^-1(x)
    Hi SHIFT,

    f(x)=x^2-1

    y=x^2-1

    Now, exchange the x and y variables. Then, solve for y.

    f'(x)\Rightarrow x=y^2-1

    y^2=x-1

    y=\sqrt{x-1}

    f'(x)=\sqrt{x-1}

    For x \ge 2 , f'(x)=[1, + \infty)
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  3. #3
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    Talking

    Note: If they'd restricted the original domain to the left-hand half of the parabola, the inverse would have involved the "minus" from the Quadratic Formula, rather than the "plus".
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