Why Multiply by Exponential Terms in Fourier Series Calculations?

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Discussion Overview

The discussion revolves around the use of exponential terms in Fourier series calculations, particularly focusing on the manipulation of terms involving sine functions and complex identities. Participants explore the application of calculus and algebra in this context.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant mentions difficulty in applying a complex identity for the sine function, indicating a potential challenge in the calculations.
  • Another participant references the fundamental theorem of calculus and suggests that both calculus and complex analysis are necessary for the problem at hand.
  • A participant expresses uncertainty about the subsequent steps after obtaining an initial result.
  • It is proposed that multiplying by an exponential term, specifically $$e^{\frac{-j\pi k}{3}}$$, could be beneficial, suggesting a strategy to simplify or manipulate the expression further.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus, as there are indications of uncertainty and differing approaches to the problem.

Contextual Notes

Some assumptions regarding the application of complex identities and the steps involved in the Fourier series calculations remain unclear, and the discussion does not resolve these uncertainties.

Who May Find This Useful

Individuals interested in Fourier series, complex analysis, and mathematical techniques in physics or engineering may find this discussion relevant.

lottotlyl
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Homework Statement
how did my prof get the last term after the third equal sign
Relevant Equations
fourier series coeffecient equation
i tired using complex identity equation for sin(pi*k/3) but it doesn't work out
 

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Physics news on Phys.org
Applying the fundamental theorem of calculus which says that
$$\int_a^b f(t)dt=F(t)\Big|_a^b=F(b)-F(a)$$ where ##F(t)## is a function satisfying $$\frac{dF(t)}{dt}=f(t).$$
Then you also need to use elemental algebra and complex analysis.
 
I got this, but I don't know the rest of the steps
 

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Well, notice that in the final answer you have the term $$e^{\frac{-j\pi k}{3}}$$ so it would be a good idea to multiply by $$1=e^{\frac{-j\pi k}{3}}e^{\frac{j\pi k}{3}}.$$
 

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