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Math Help - Please can anyone help to give the derivative of this beast!

  1. #1
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    Please can anyone help to give the derivative of this beast!

    f(x)= x^3 + \frac{3}{2} x^2 - \frac{135}{16} x + \frac{25}{4}

    like in terms of if the question were for f(x)=cosx-x then its derivative would be f'(x) = -sinx-1?

    Thanks fo rany help/advise

    Steve
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  2. #2
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    is it just  f(x) = 3x^2 ?
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  3. #3
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    Quote Originally Posted by maxmadx View Post
    f(x)= x^3 + \frac{3}{2} x^2 - \frac{135}{16} x + \frac{25}{4}

    like in terms of if the question were for f(x)=cosx-x then its derivative would be f'(x) = -sinx-1?

    Thanks fo rany help/advise

    Steve
    It is,
    (x^3)' + \frac{3}{2} (x^2)' - \frac{135}{16}(x)' + \left( \frac{25}{4} \right) '
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  4. #4
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    3x^2 + 3x - 135/16
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  5. #5
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by Paige05 View Post
    3x^2 + 3x - 135/16
    Yup!

    -Dan
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  6. #6
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    Hi, can I ask why an online derivative calculator gives:

    3x^2 + (3/2)2x-135/16


    which is different?
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  7. #7
    Forum Admin topsquark's Avatar
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    Quote Originally Posted by maxmadx View Post
    Hi, can I ask why an online derivative calculator gives:

    3x^2 + (3/2)2x-135/16


    which is different?
    That middle term simplifies to what I gave you. I presume the program isn't simplifying the result and if you put a fraction in front of, say the x^3 term, you would see a similar result.

    -Dan
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