Solving a complex equation with roots of unity

Click For Summary
SUMMARY

The equation (z+1)^5 = z^5 can be solved using roots of unity. By rewriting the equation as 1 = ((z+1)/z)^5, the solutions can be derived from the fifth roots of unity. The specific roots are given by w = exp(i*2k*pi/5) for k = 1, 2, 3, 4, leading to the solutions z = 1/(1-w). This method provides a systematic approach to finding all complex solutions to the equation.

PREREQUISITES
  • Understanding of complex numbers and their properties
  • Familiarity with roots of unity and their applications
  • Knowledge of exponential functions in the context of complex analysis
  • Basic algebraic manipulation skills
NEXT STEPS
  • Study the properties of complex numbers and their geometric interpretations
  • Learn about the derivation and applications of roots of unity
  • Explore the use of exponential functions in solving complex equations
  • Practice solving similar equations using algebraic and geometric methods
USEFUL FOR

Mathematics students, educators, and anyone interested in complex analysis and solving polynomial equations using advanced techniques.

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.
 

Similar threads

  • · Replies 9 ·
Replies
9
Views
4K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
4K
  • · Replies 22 ·
Replies
22
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K