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    The stationary points of the equation:

    y = 2x^3 + 7/2 x^2 - 3x +1

    The x values are 1/3 and -3/2, that gives y values of 25/54 and 53/8 respectively.

    The text book has the y value when x=1/3 as -25/54.

    What am I doing wrong as no matter what I do I can't get a negative when x=1/3?

    Or is there a typo in the answers given and it should be +25/54?
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    (Original post by gerrya271)
    The stationary points of the equation:

    y = 2x^3 + 7/2 x^2 - 3x +1

    The x values are 1/3 and -3/2, that gives y values of 25/58 and 53/8 respectively.

    The text book has the y value when x=1/3 as -25/58.

    What am I doing wrong as no matter what I do I can't get a negative when x=1/3?

    Or is there a typo in the answers given and it should be +25/58?
    Typo, though it should be 54 not 58 on the denom.
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    (Original post by RDKGames)
    Typo, though it should be 54 not 58 on the denom.
    Yeah sorry, I have 54 on the bottom not 58.

    So it's deffo positive and therefore a typo in the answers in the book?
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    (Original post by gerrya271)
    Yeah sorry, I have 54 on the bottom not 58.

    So it's deffo positive and therefore a typo in the answers in the book?
    Yes. Graph it yourself on some software if you need convincing.
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    (Original post by RDKGames)
    Yes. Graph it yourself on some software if you need convincing.
    I just wanted to double check as I tutor my daughters and her friends for Maths and it simply didn't seem possible to get a negative answer when x=1/3, but it's always a bit off putting when the answers in the back of the book say otherwise.

    Thank you for confirming that I've not suddenly lost my ability to count!!
 
 
 
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