The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Complex numbers help

Screen Shot 2016-04-11 at 20.49.08.png

Can anyone help me with part a) at least? Thanks in advance any hep is appreciated.
Reply 1
Avatar for RyanW97
RyanW97
2
Original post by ThomsonM98
Screen Shot 2016-04-11 at 20.49.08.png

Can anyone help me with part a) at least? Thanks in advance any hep is appreciated.


You can express a complex number as x + iy so the question is asking you to solve (x + iy)^4 = i - 3

Expand the brackets, equate real and imaginary parts and solve the simultaneous equations.

I haven't worked through it so I assume that's the right method!
Reply 2
Avatar for Zacken
Zacken
22
Original post by ThomsonM98
Screen Shot 2016-04-11 at 20.49.08.png

Can anyone help me with part a) at least? Thanks in advance any hep is appreciated.


Write i−3i - 3 in polar form then use De-Moivre's theorem.
Reply 3
Avatar for RyanW97
RyanW97
2
Original post by Zacken
Write i−3i - 3 in polar form then use De-Moivre's theorem.


This will be a much easier way to solve it, ignore my last reply!
Reply 4
Avatar for B_9710
B_9710
18
Wrte −3+i -3+i in polar form or, as i usually prefer myself, in exponential form. I think in exponential form, De Movire's theorem seems very intuitive that way as it just becomes simple laws of indices.
Reply 5
Avatar for Zacken
Zacken
22
Original post by B_9710
Prefer exponential form.


I agree with this, the only drawback is that you have to shove your arguments (which can sometimes be hairy) into the tiny space above your ee, but that's easily remedied by using exp⁡\exp instead.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you