Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

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


    User Avatar
    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".
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook