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Math Help - derivatives

  1. #1
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    derivatives

    f(x) = 4x^2 - 5x, when f'(2) equals?



    How am I supposed to figure this out without being given the points for x and f(a)?
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  2. #2
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    Quote Originally Posted by obsmith08 View Post
    f(x) = 4x^2 - 5x, when f'(2) equals?



    How am I supposed to figure this out without being given the points for x and f(a)?
    In order to do this problem, u first have to find the derivative of f(x). So u find the derivative of f(x), f'(x)=2*4x^(2-1)-1*5x^(1-1) which gives u f'(x)=8x-5. Once you have this just plug in 2 into the f'(x) equation which gives you 16-5=11
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  3. #3
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    Smile

    Quote Originally Posted by ahawk1 View Post
    In order to do this problem, u first have to find the derivative of f(x). So u find the derivative of f(x), f'(x)=2*4x^(2-1)-1*5x^(1-1) which gives u f'(x)=8x-5. Once you have this just plug in 2 into the f'(x) equation which gives you 16-5=11

    I worked through finding the derivative and got 8x-5=11! with your help! Thanks so much!
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