Results 1 to 3 of 3

Math Help - Complex Equation Help!

  1. #1
    Newbie
    Joined
    Nov 2009
    Posts
    3

    Complex Equation Help!

    So, I'm having trouble with these complex equations. Any help would be great!

    (2+3i)(3-4i)

    2+i/3i

    1+2i/1-i

    Thanks again.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member
    Joined
    Nov 2009
    Posts
    277
    Thanks
    2
    Lets try something like your problems

    (3+4i)(1+2i)
    = 3*1 + 4i*1 + 3*2i + 4i*2i
    = 3 + 4i + 6i + 8i^2
    = 3 - 8 + 10i
    = -5 + 10i.

    See how it's done?

    (3+4i) / ( 2+i )
    = (3+4i)(2-i) / (2+i)(2-i) multiply by 1, where 1 = (2-i)/(2-i).
    = multiply out the top / multiply out the bottom.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Senior Member Stroodle's Avatar
    Joined
    Jun 2009
    Posts
    367
    Remember that i^2=-1 and if you multiply a complex number by its conjugate you will get a real number.

    e.g. the conjugate of a+bi is a-bi
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Complex equation: z^6 +3z^3 + 1 = 0
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: March 29th 2011, 07:52 PM
  2. Complex equation
    Posted in the Calculus Forum
    Replies: 6
    Last Post: June 20th 2010, 11:22 PM
  3. complex equation
    Posted in the Differential Geometry Forum
    Replies: 1
    Last Post: January 29th 2010, 03:38 AM
  4. Complex equation
    Posted in the Algebra Forum
    Replies: 1
    Last Post: April 21st 2008, 04:38 AM
  5. A complex equation
    Posted in the Calculus Forum
    Replies: 7
    Last Post: December 8th 2006, 05:38 PM

Search Tags


/mathhelpforum @mathhelpforum