1. Limited time only! Sign up for a free 30min personal 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!

Imaginary multiplication with answer to be in polar (variables)

  1. Mar 5, 2006 #1
    I have to find (a+bi)(c+di) in polar form given that b,c,d>0 and a<0.

    So I convert each one to polar first.

    [tex]( (a+b)cis(\arctan(-b/a) + \pi) ) ( (c+d)cis(\arctan(d/c)) )[/tex]

    That's as far as I got. Little help please?
    Last edited: Mar 5, 2006
  2. jcsd
  3. Mar 5, 2006 #2
    Multiply the numbers out first. Then you will have just one complex number. Then just find the modulus and argument using pythagoras and arctan like you mentioned.
  4. Mar 5, 2006 #3
    That would give -(ac) -(adi) +(bci) -(bd)?

    But how do I find a modulus and argument with that?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Imaginary multiplication with answer to be in polar (variables)