Solving a complex equation with roots of unity

Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
1 reply · 3K views
Clouded
Messages
2
Reaction score
0

Homework Statement



z is a complex number.

Find all the solutions of

(z+1)^5 = z^5

The Attempt at a Solution



Of course one could expand (z+1)^5, but I remeber our professor solving this with roots of unity. Can anyone help?
 
Physics news on Phys.org
Ah, embarissing.

1=(z+1)^5/z^5
=((z+1)/z)^5

and then just using the roots of unity to find z= 1/(1-w) , w=exp(i*2k*pi/5), k=1,2,3,4.