Complex number and power series

In summary, the task is to find the power series for e^z + e^(ωz) + e^((ω^2) z), given that ω = e^(2πi/3). The solution involves writing out the three individual power series and summing them, then collecting like powers of z. The equation 1+w+w^2=0 can be used to simplify the coefficients, and looking at specific cases such as n=0,1,2,3 can help to generalize the solution.
  • #1
rainwyz0706
36
0

Homework Statement



Let ω be the complex number e^(2πi/3), Find the power series for e^z + e^(ωz) + e^((ω^2) z).




Homework Equations





The Attempt at a Solution


I can show that 1+w+w^2=0, don't know if it would help. Could anyone please give me some hints? Any input is appreciated!
 
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  • #2
Write out the three individual power series and sum them. Collect like powers of z. Use your equation for w to try and simplify the coefficients.
 
  • #3
I can write it as the sum of (z^n)*(1+w^n+w^2n)/n!, n from 0 to infinity. But I'm still not sure how to simplify 1+w^n+w^2n from 1+w+w^2=0. Could you explain it in a bit more details? Thanks a lot!
 
  • #4
rainwyz0706 said:
I can write it as the sum of (z^n)*(1+w^n+w^2n)/n!, n from 0 to infinity. But I'm still not sure how to simplify 1+w^n+w^2n from 1+w+w^2=0. Could you explain it in a bit more details? Thanks a lot!

Look at the n=0,1,2,3 cases. Hint, what's w^3? Once you've got those you should find it pretty easy to generalize.
 
  • #5
thanks, I got it!
 

What is a complex number?

A complex number is a number that is expressed in the form a + bi, where a and b are real numbers and i is the imaginary unit, defined as the square root of -1. Complex numbers are commonly used in mathematics and physics to represent quantities that have both real and imaginary components.

What is the difference between a real number and a complex number?

A real number is a number that can be expressed on a number line, and includes all positive and negative numbers as well as zero. A complex number, on the other hand, has both a real and an imaginary component and cannot be represented on a number line. In other words, a complex number is a superset of real numbers.

What is a power series?

A power series is an infinite series in the form of a polynomial, where the coefficients of the terms increase in a specific pattern. It is commonly used in calculus to represent a function as an infinite sum of simpler functions. Power series are also useful for approximating functions and solving differential equations.

How are complex numbers and power series related?

Complex numbers can be used to represent the coefficients in a power series, allowing for the representation of complex functions. Power series can also be used to approximate complex functions, making them an important tool in the study of complex numbers.

What are some real-life applications of complex numbers and power series?

Complex numbers and power series are used in a variety of fields, including electrical engineering, physics, and signal processing. They are used in the study of alternating current circuits, quantum mechanics, and Fourier analysis, among others. They are also used in computer graphics and animation to create 3D effects.

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