1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

[HELP] Derivative Of The Exponential !

  1. Jan 8, 2010 #1
    hi guys

    I need The proof from definition of the derivative for exponential and log Fn
    can somebody help me !!
     
  2. jcsd
  3. Jan 8, 2010 #2

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi MiniSmSm! Welcome to PF! :smile:

    Let's start with the exponential.

    First, what definition of the exponential function are you using?
     
  4. Jan 8, 2010 #3
    Welcome Tiny-tim

    I use e^x or a^x
     
  5. Jan 8, 2010 #4

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi MiniSmSm! :smile:

    (try using the X2 tag just above the Reply box :wink:)

    Yes, but how are you defining ex ?
     
  6. Jan 8, 2010 #5
    I don understand !
    I mean as a power series
     
  7. Jan 8, 2010 #6

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    You mean ∑0 xn/n! ?

    ok, then just differentiate that …

    what do you get? :smile:
     
  8. Jan 8, 2010 #7
    No no ..

    I mean by using this formula

    F(x+h)-F(x) / h ( sorry I don`t know how to use tags :( )

    how can I prove that the derivative of that function equals to its own !
     
  9. Jan 8, 2010 #8
  10. Jan 8, 2010 #9
    thank you
    this is what I wanted
     
  11. Jan 9, 2010 #10

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    That proof requires the fact that [itex]e^{x+y}= e^xe^y[/itex]. Have you proved that from the power series definition? If so, how?
     
  12. Jan 10, 2010 #11
    Actually I haven`t :(
    how ?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: [HELP] Derivative Of The Exponential !
  1. Exponential Derivative (Replies: 7)

Loading...