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Math Help - does anyone understand this?

  1. #1
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    does anyone understand this?

    Problem:
    f(x)=x^3, find f^-1 (-8)

    help please
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  2. #2
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    Quote Originally Posted by lsnyder View Post
    Problem:
    f(x)=x^3, find f^-1 (-8)

    help please
    y = x^3 \implies x=\sqrt[3]{y}

    f^{-1}(x) = \sqrt[3]{x}

    Can you find f^{-1}(8) now?
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  3. #3
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    Quote Originally Posted by lsnyder View Post
    Problem:
    f(x)=x^3, find f^-1 (-8)

    help please
    Solve -8 = x^3: x = -2. Therefore f(-2) = -8. Therefore by definition f^{-1}(-8) = -2.
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  4. #4
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    Quote Originally Posted by Chop Suey View Post
    y = x^3 \implies x=\sqrt[3]{y}

    f^{-1}(x) = \sqrt[3]{x}

    Can you find f^{-1}(8) now?

    yes thank u very much
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