Find the root of the complex 3+4i

What we should know is that the root 3+4i is a complex number that looks alot like a+bi.

We can say : rt(3+4i) = a+bi (Where we dont know what a & b is..yet)

and when we square both sides (rt(3+4i))^2=(a+bi)^2 | 3+4i = (a+bi)^2

we get 3+4i = a^2+2abi-b^2

We seperate the Real and Imaginary parts to get a simultainus equation

3 = a^2-b^2

4 = 2ba

if this is solved we get a= (+-)2 and b =(+-)1

to get (+-)(2+i) <--- which is the answer

AA
Answered by Ade A. Further Mathematics tutor

3056 Views

See similar Further Mathematics A Level tutors

Related Further Mathematics A Level answers

All answers ▸

Can you express 3 + 4j in polar form?


How do you invert a 2x2 matrix?


Particles P and Q move in a plane with constant velocities. At time t = 0 the position vectors of P and Q, relative to a fixed point O in the plane, are (16i - 12j) m and -5i + 4j) m respectively. The velocity of P is (i + 2j) m/s and the velocity of Q


Find the values of x where x+3>2/(x-4), what about x+3>2/mod(x-4)?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences