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Math Help - Please help me find the global minimum/maximum of the following

  1. #1
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    Please help me find the global minimum/maximum of the following

    f(x) = 4x^3 - 8squarerootx for 0 equal/less x equal/less 10

    I've got thus far
    y' = 12x^2 - (4/squarerootx)
    when y' = 0, x = 0.64439
    y'' = 24x + 2x^-1.5
    when x = 0.64439, y'' = 19.33, which is a local minimum
    y-coordinate of x = 0.64439 is -5.35
    Left boundary x = 0, y = 0
    Right boundary x = 10, y = 3,974.70

    and I know how to draw the graph

    okay so what is the global minimum/maximum? What does that mean?
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  2. #2
    Master Of Puppets
    pickslides's Avatar
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    Which one is your function?

    f(x) = 4x^3 - \sqrt[8]{x} ~, ~0 \leq x \leq 10

    or

    f(x) = 4x^3 - 8\times \sqrt{x} ~ , ~0 \leq x \leq 10
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  3. #3
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    It's the 2nd one, but don't worry as I've figured out the answers now
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