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

Homework Help: Help rewriting an equation

  1. Nov 3, 2004 #1
    I am trying to rewrite -i arctan ix = arctanh x + c as
    e^it = cos t + i sin t

    I am having trouble rewriting
    sqrt[ 1 + i tan t / 1 - i tan t]

    as
    cos t + i sin t

    Is this possible or did I do something wrong?
    What do I multiply the sqrts by.
     
  2. jcsd
  3. Nov 3, 2004 #2

    Hurkyl

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    When one is lost, it often helps to rewrite all trig functions in terms of sine and cosine.
     
  4. Nov 3, 2004 #3
    How does that help here?
     
  5. Nov 4, 2004 #4
    I just need help with the algebra, if my substitutions are correct
     
  6. Nov 4, 2004 #5

    Hurkyl

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Because it usually helps you see the necessary manipulations. Besides, the answer you seek is in terms of sines and cosines, so you'll have to do it sometime anyways.
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook