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Question about product rule

  1. Sep 29, 2011 #1

    It is given that h(x) = f(x)g(x). It then tells me to write a formula for h'(2).

    I know that h'(x) = f'(x)g(x) + f(x)g'(x), using the product rule.

    So I assumed that h'(2) = f'(2)g(2) + f(2)g'(2)

    Is this correct? Does the product rule simply allow me to do this? It seems to simple.

    Thanks in advance,

    Last edited: Sep 29, 2011
  2. jcsd
  3. Sep 29, 2011 #2
    Looks correct to me. You were expecting something really complicated?
  4. Sep 30, 2011 #3
    I'm in calculus 1, so this stuff is fairly new to me. Just making sure I wasn't missing something. Thanks!!
  5. Sep 30, 2011 #4


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    Staff Emeritus
    Science Advisor

    Yes, if a function is given by f(x)= really complicated stuff with the letter "x" in it, then
    f(2)= really complicated stuff with the letter "x" replaced by the number 2.

    That has nothing to do with the derivative, per se, but with "function notation".
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