Results 1 to 3 of 3

Math Help - Having issues with this complex numbers question

  1. #1
    Newbie
    Joined
    Mar 2008
    Posts
    5

    (Self-solved) Help: complex numbers question

    Hi,

    I'm looking at this question while practising and I still don't really understand the question entirely. I'm extremely bad with this chapter, not very good at understanding questions and am in need of some help or guidelines with going about doing it.


    "The parallegram OABC, described in an anticlockwise sense where O is the origin, lies in the first quadrant in which OA = 3 OC and ∠COA = 30 . The vertices A, B, C represent the complex numbers a, b, c respectively. Express the complex number c/a in polar form.

    Given that a = 6 + i, find b and c in their simplest exact form."



    I'm really not sure if parellegram refers to parellelogram but either way, I'm still stuck.

    I'm given these solutions for this question.

    1/3 (cos 30 + i sin 30 ); b = (35/6 + √3) + (2 + √3/6 i), c = (√3 - 1/6) + (1 + √3/6 i)

    For the first part, I was thinking that since OA = 3OC, OC is 1/3 of OA and hence the answer but my gut feeling was that my logic was way too simple..

    For second part, I tried using the following. This is the way I see the question:

    http://i258.photobucket.com/albums/h..._complexno.png

    http://i258.photobucket.com/albums/h..._complexno.png

    http://i258.photobucket.com/albums/h..._complexno.png

    What I got was c = 1/6 √111 + (1/6 √37) i
    I don't know where I've gone terribly wrong, and felt discouraged so I did not do calculations for b...
    Last edited by Puzzled; March 10th 2008 at 05:10 AM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Newbie
    Joined
    Mar 2008
    Posts
    5
    I think I thought too far for this one, managed to get c now without drawing any pictures...I'll try B later but I have no idea what to do from now also...



    Please help if you know
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Mar 2008
    Posts
    5
    Ok stupid me managed to solve it...a + c = b...
    I feel like a noob...
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Question(s) about complex numbers.
    Posted in the Algebra Forum
    Replies: 5
    Last Post: January 1st 2010, 01:16 PM
  2. Complex numbers question
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: December 15th 2009, 07:56 AM
  3. Complex Numbers Question
    Posted in the Advanced Algebra Forum
    Replies: 3
    Last Post: April 2nd 2008, 06:48 AM
  4. complex numbers, a question
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: April 16th 2007, 10:05 AM
  5. complex numbers question
    Posted in the Algebra Forum
    Replies: 2
    Last Post: October 14th 2006, 11:15 PM

Search Tags


/mathhelpforum @mathhelpforum