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!

Calculating complex number

  1. May 19, 2008 #1
    [SOLVED] calculating complex number

    1. The problem statement, all variables and given/known data

    Calculate [tex]{i}^{\frac{3}{4}}[/tex]

    2. Relevant equations



    3. The attempt at a solution

    I tried with

    [tex]i=cos\frac{pi}{2}+isin\frac{\pi}{2}[/tex]

    [tex]i^3=cos\frac{3pi}{2}+isin\frac{3\pi}{2}[/tex]

    [tex]i^3=-i[/tex]

    [tex]\sqrt[4]{i^3}=\sqrt[4]{-i}[/tex]

    I don't know where I should go out of here. Please help!
     
  2. jcsd
  3. May 19, 2008 #2

    Dick

    User Avatar
    Science Advisor
    Homework Helper

    Why don't you just go all the way at once? i=e^(i*pi/2). So i^(-3/4)=(e^(i*pi/2))^(-3/4). Now use laws of exponents. Notice this answer isn't unique. i is also equal to e^(i*(pi/2+2pi)=e^(i*5pi/2). This is the same sort of nonuniqueness you get with square roots.
     
  4. May 20, 2008 #3
    Thanks. I solve it.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Calculating complex number
  1. Complex numbers (Replies: 6)

  2. Complex numbers (Replies: 6)

Loading...