Login

Welcome, Guest. Please login or register.

November 01, 2025, 03:22:39 pm

Author Topic: solutions of a complex number equation  (Read 1047 times)  Share 

0 Members and 1 Guest are viewing this topic.

M-D

  • Victorian
  • Forum Obsessive
  • ***
  • Posts: 227
  • Respect: 0
solutions of a complex number equation
« on: May 05, 2013, 06:59:48 pm »
0
Hi,

i need to find the roots for z^5=32i only in exponential form. Here are the ones i got:

2e^i*pi/10
2e^i*pi/2
2e^i*9pi/10
2e^i*13pi/10=2e^-i*7pi/10 (principal argument)
2e^i*17pi/10=2e^-i3pi/10 (principal argument)
 
are they correct. I appreciate your help

Alwin

  • Victorian
  • Forum Leader
  • ****
  • Posts: 838
  • Respect: +241
Re: solutions of a complex number equation
« Reply #1 on: May 05, 2013, 07:40:33 pm »
+1
Hi,

i need to find the roots for z^5=32i only in exponential form. Here are the ones i got:

2e^i*pi/10
2e^i*pi/2
2e^i*9pi/10
2e^i*13pi/10=2e^-i*7pi/10 (principal argument)
2e^i*17pi/10=2e^-i3pi/10 (principal argument)
 
are they correct. I appreciate your help

Yes, that's correct.
2012:  Methods [48] Physics [49]
2013:  English [40] (oops) Chemistry [46] Spesh [42] Indo SL [34] Uni Maths: Melb UMEP [4.5] Monash MUEP [just for a bit of fun]
2014:  BAeroEng/BComm

A pessimist says a glass is half empty, an optimist says a glass is half full.
An engineer says the glass has a safety factor of 2.0

lzxnl

  • Victorian
  • ATAR Notes Legend
  • *******
  • Posts: 3432
  • Respect: +215
Re: solutions of a complex number equation
« Reply #2 on: May 05, 2013, 08:44:40 pm »
0
Well as an easy check if your solution makes sense, check the magnitudes of both sides. Here, |z|=2 as you can tell. Next, confirm that one of your answers is correct. In this case, we'll check that 2e^(i*pi/2) is correct, and it is, as that is 2i and (2i)^5 is clearly 32i. Finally, check that the arguments of all of your answers are spaced out evenly by 2pi/n. You can check this one.
2012
Mathematical Methods (50) Chinese SL (45~52)

2013
English Language (50) Chemistry (50) Specialist Mathematics (49~54.9) Physics (49) UMEP Physics (96%) ATAR 99.95

2014-2016: University of Melbourne, Bachelor of Science, Diploma in Mathematical Sciences (Applied Maths)

2017-2018: Master of Science (Applied Mathematics)

2019-2024: PhD, MIT (Applied Mathematics)

Accepting students for VCE tutoring in Maths Methods, Specialist Maths and Physics! (and university maths/physics too) PM for more details