1. Limited time only! Sign up for a free 30min personal 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!

Simple question

  1. Sep 16, 2005 #1
    just starting up the school year again and my brain is not there yet.

    Is e^x an even or odd function.

    also what about
    e^x + e^-x

    and

    e^x - e^-x

    thanks for the help.
     
  2. jcsd
  3. Sep 16, 2005 #2

    shmoe

    User Avatar
    Science Advisor
    Homework Helper

    Have you tried to apply the definitions of even and odd functions? Where does it get you?
     
  4. Sep 16, 2005 #3
    it gets me nowhere. applying the definition and inserting -x into e^x just gives (1/e^x) which is neither f(x) nor -f(x).
     
  5. Sep 16, 2005 #4
    a function is even iff f(-x) = f(x), for example cos(x)
    a function is odd iff f(-x) = -f(x), for example sin(x)

    exp(-x) <> exp(x) <> -exp(x), so exp(x) is neither
    exp(-x)+exp(x) = exp(x)+exp(-x), so exp(x)+exp(-x) is even (=2cos(x))
    exp(-x)-exp(x) = -(exp(x)-exp(-x)), so exp(x)-exp(-x) is odd (=2isin(x))
     
  6. Sep 16, 2005 #5
    Another approach, graphically. An even function is symmetric to the y-axis, an odd function symmetric to the origin. Graph you functions and see what you come up with.
     
  7. Sep 16, 2005 #6

    shmoe

    User Avatar
    Science Advisor
    Homework Helper

    It's possible for a function to be neither even nor odd.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Simple question
  1. A simple question? (Replies: 2)

  2. Simple Question (Replies: 0)

  3. Simple Question (Replies: 4)

  4. A simple question (Replies: 3)

Loading...