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Math Help - Help with procedures please

  1. #1
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    Help with procedures please

    *A model for the height of a toy rocket shot from a platform is y=-16x^2+145x+7, where x is the time in seconds and y is the height in feet.
    a)Graph the function
    b)Find the zeros of the function( i get a weird root)
    c)What do the zeros represent? Are tehy realistic? (answered)
    d)About how high does the rocket fly before hitting the ground? explain???

    *what are multiple zeroes? Explain how you can tell if a function has multiple zeroes.

    *A polynomial equation with rational coefficeints has root of 7 and negative root of 3. Explain how to find two additional roots and name them.
    I know that hte additional roots will be negative root of 7 and positive root of 3... what do you mean by name them?

    Thanks for the help
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  2. #2
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by jjkins View Post
    *A model for the height of a toy rocket shot from a platform is y=-16x^2+145x+7, where x is the time in seconds and y is the height in feet.
    a)Graph the function
    b)Find the zeros of the function( i get a weird root)
    c)What do the zeros represent? Are tehy realistic? (answered)
    d)About how high does the rocket fly before hitting the ground? explain???
    Surely you can graph this yourself?

    Yes, the zeros are kind of ugly, aren't they? I get
    \frac{145 \pm \sqrt{21473}}{32}

    As to how high it gets there are two ways depending on which class you are in.
    1) Complete the square to put the quadratic in vertex form. The y value at the vertex is the highest point.
    2) Use the first derivative of y to find the absolute maximum of the function.

    Quote Originally Posted by jjkins View Post
    *what are multiple zeroes? Explain how you can tell if a function has multiple zeroes.
    A polynomial will have multiple zeros (or perhaps none at all!) if the degree of the polynomial is greater than 1. As far as non-polynomials are concerned I have no idea how to show this without actually solving for the zeros.

    Quote Originally Posted by jjkins View Post
    *A polynomial equation with rational coefficeints has root of 7 and negative root of 3. Explain how to find two additional roots and name them.
    I know that hte additional roots will be negative root of 7 and positive root of 3... what do you mean by name them?
    You are correct. "Naming" them simply means tell what they are.

    -Dan
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