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

What Basic Derivative Rule Is Responsible For This?

  1. Sep 22, 2009 #1




    Please note that the sum/difference rule is not directly invoked since it talks about a derivative of a sum/difference being equal to the sum/difference of the derivatives. It could very well be the basis for this logic, although I don't see it offhand. And of course, this is not a homework question. I came across this logic today and was surprised I could use it.
    Last edited: Sep 22, 2009
  2. jcsd
  3. Sep 22, 2009 #2


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member

    It certainly is the sum-difference rule. When you compute a'(x) on the left you are asking for (b(x) - c(x))' on the right, which, by the difference rule is b'(x) - a'(x).
  4. Sep 22, 2009 #3
    Ah yes! Thank you. All I had to do was write "d(b-c)" instead of "da" and I would have seen it immediately.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook