Simple Complex Number Question (Roots of 1)

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SUMMARY

The discussion centers on the calculation of the complex fifth roots of unity using Euler's equation. The correct arguments for the fifth roots are identified as 0, 2π/5, 4π/5, 6π/5, and 8π/5. The user incorrectly expressed e^(i2π/5) as 1^(1/5), which is factually incorrect since 1^(1/5) only represents the principal root of unity. The consensus is that the user should clarify their expression to avoid confusion, but they successfully identified the correct roots.

PREREQUISITES
  • Understanding of complex numbers and their properties
  • Familiarity with Euler's formula (e^(ix) = cos(x) + i*sin(x))
  • Knowledge of roots of unity in complex analysis
  • Basic algebraic manipulation of exponential expressions
NEXT STEPS
  • Study the derivation and implications of Euler's formula in complex analysis
  • Learn about the general formula for finding nth roots of unity
  • Explore the geometric interpretation of complex roots on the unit circle
  • Review common mistakes in expressing roots of unity and how to avoid them
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Students studying complex analysis, particularly those working on problems involving roots of unity and Euler's formula. This discussion is beneficial for anyone looking to clarify their understanding of complex exponentiation and its applications.

bmb2009
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Homework Statement


So on one of my homework assignments I had to find the complex fifth roots of one. Because of Euler's equation the arguments are simply 0, 2pi/5,4pi/5,6pi/5,and 8pi/5. It is easy to see that (e^i2pi/5)^5 = (e^i2pi) = cos(2pi) + isin(2pi) = 1 + 0 = 1 but on my paper I wrote e^(i2pi/5) = 1^(1/5) and similar expressions for all the arguments of the fifth roots and lost 10 point out of 15. I wanted to ask the TA to regrade it but I don't want to bother him if I'm flat out wrong expressing the way I did? Any input would be great.. Thanks!


Homework Equations





The Attempt at a Solution

 
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bmb2009 said:

Homework Statement


So on one of my homework assignments I had to find the complex fifth roots of one. Because of Euler's equation the arguments are simply 0, 2pi/5,4pi/5,6pi/5,and 8pi/5. It is easy to see that (e^i2pi/5)^5 = (e^i2pi) = cos(2pi) + isin(2pi) = 1 + 0 = 1 but on my paper I wrote e^(i2pi/5) = 1^(1/5) and similar expressions for all the arguments of the fifth roots and lost 10 point out of 15. I wanted to ask the TA to regrade it but I don't want to bother him if I'm flat out wrong expressing the way I did? Any input would be great.. Thanks!

Homework Equations


The Attempt at a Solution


Saying e^(i2pi/5) = 1^(1/5) is flat out wrong. 1^(1/5) doesn't mean ANY fifth root of 1. It means 1. Saying (e^(i2pi/5))^5=1 is really what you meant. Still you got the roots. Up to you whether to appeal.
 
Last edited:

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