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Thread: Maximum and Minimum

  1. #1
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    Maximum and Minimum

    under the condition 2x+y=4 for real numbers x, y, the maximum value of 4x + y is.....and the minimum one is .....
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  2. #2
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    Re: Maximum and Minimum

    show some work
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  3. #3
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    Re: Maximum and Minimum

    I thought...
    y = 4 - 2x

    4x + y = 4x + 4 - 2x.....

    maximum is (1,6), but the minimum?


    I thought
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  4. #4
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    Re: Maximum and Minimum

    by derivate i get the maximum point but and the minimum?
    Last edited by provasanteriores; Jan 6th 2017 at 10:21 AM.
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  5. #5
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    Re: Maximum and Minimum

    note that $2x^2+y^2 = 4$ is an ellipse with $-\sqrt{2} \le x \le \sqrt{2}$ and $-2 \le y \le 2$

    the value of $4x+y^2$ will be a minimum when $x = -\sqrt{2}$ and $y=0$
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  6. #6
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    Re: Maximum and Minimum

    thanks!!!
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