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Homework Help: Derivative help

  1. Jan 24, 2005 #1
    p is a real number
    f(x)=1+2p(x-1)+(x-1)^2 for x=<1

    My book says that the derivative of this function is:

    Shouldnt it be 2p+2(x-1)+2(x-1)

    since the derivative of 2p(x-1) is 2p+2(x-1)
    and the derivative of (x-1)^2 is 2(x-1)
  2. jcsd
  3. Jan 24, 2005 #2
    p is a real number. It is constant.
  4. Jan 24, 2005 #3


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    Homework Helper

    You're misapplying the product rule here.
  5. Jan 24, 2005 #4


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    this is what i got

    f(x)=1+2p(x-1)+(x-1)^2 for x=<1
    f'(x)= 0(x-1) + 2p(1) + 2(x-1)(1)
    = 2p + 2(x-1)

    use product rule and chain rule
    hope that helps...

    - Tu
    Last edited: Jan 24, 2005
  6. Jan 24, 2005 #5


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    the derivitive of 2p(x-1) is:

    0(x-1) + 2p(1) which gives u 2p using the product rule

    note that p is a constant so when u take the derivitive of it its just a plain 0... sorry i suck at explaining...

    - Tu
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