Results 1 to 5 of 5

Thread: re^itheta

  1. #1
    Super Member
    Joined
    Feb 2008
    Posts
    535

    re^itheta

    I'm asked to express 4 in the form re^i*theta

    Here's what i've done:

    r = squreRoot(4^2 + 0^2)
    r = 4

    How do I find theta?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Aug 2009
    From
    Israel
    Posts
    976
    $\displaystyle 4 = 4 +0\cdot i$, so $\displaystyle \theta = arctan \left( \frac{0}{4} \right) = arctan(0)$
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member
    Joined
    Feb 2008
    Posts
    535
    Ok, then 4 written in this form is just simply 4 since 4e^i*0 = 4. RIght?

    How about this one: 3i

    r = 3, but theta = arctan(3/0)??? 3 divided by 0...
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    Prove It's Avatar
    Joined
    Aug 2008
    Posts
    12,880
    Thanks
    1946
    Well, $\displaystyle 3i$ lies on the positive imaginary axis.

    What is the angle made?
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    9
    Quote Originally Posted by jzellt View Post
    I'm asked to express 4 in the form re^i*theta

    Here's what i've done:

    r = squreRoot(4^2 + 0^2)
    r = 4

    How do I find theta?
    Quote Originally Posted by jzellt View Post
    [snip]
    How about this one: 3i

    r = 3, but theta = arctan(3/0)??? 3 divided by 0...
    If you had plotted 4 and 3i on an Argand diagram it would be completely obvious what the argument of each is.
    Follow Math Help Forum on Facebook and Google+

Search tags for this page

Click on a term to search for related topics.

Search Tags


/mathhelpforum @mathhelpforum