What is the process for determining Fourier coefficients?

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Discussion Overview

The discussion revolves around the process of determining Fourier coefficients, specifically addressing the interpretation of an equation involving a summation and its implications. Participants explore the meaning of the equation and its components, seeking clarification on notation and terminology.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant, Josh, asks whether the equation \(\sum_{i=1}^{n}A_i=i\) is equivalent to stating \(A_i=i\) and seeks an explanation.
  • Another participant expresses confusion regarding the equation, noting that \(i\) is typically an index variable and questions its meaning on the right side of the equation.
  • A third participant clarifies that the equation can be interpreted as \(A_1 + A_2 + \cdots + A_n = i\), explaining that the \(i\) in the summation is a bound variable and suggesting that using \(i\) in both contexts is problematic.
  • Josh mentions that he was trying to generalize for determining Fourier coefficients and provides a link to a previous discussion for further context.

Areas of Agreement / Disagreement

Participants express varying levels of understanding regarding the notation and implications of the equation. There is no consensus on the interpretation of the equation, and confusion remains about the use of the index variable.

Contextual Notes

The discussion highlights potential limitations in notation clarity and the need for precise definitions when dealing with summations and index variables. The implications of using the same symbol for different purposes in mathematical expressions are also noted.

Who May Find This Useful

Readers interested in mathematical notation, summation conventions, and the determination of Fourier coefficients may find this discussion relevant.

member 428835
hey pf!

can someone explain to me what to do if presented with an equation like this: [tex]\sum_{i=1}^{n}A_i=i[/tex]
is this identical to stating [itex]A_i=i[/itex]? either way, can you please explain.

thanks!

josh
 
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joshmccraney said:
hey pf!

can someone explain to me what to do if presented with an equation like this: [tex]\sum_{i=1}^{n}A_i=i[/tex]
is this identical to stating [itex]A_i=i[/itex]? either way, can you please explain.

thanks!

josh
It doesn't make much sense to me. On the left side, i is an index variable that takes on the values 1, 2, 3, ..., n, so I have no idea what it means on the right side.

Where did you see this? If it's from a textbook, can you post a picture?
 
Just taking it at face value, it means
##A_1 + A_2 + \cdots + A_n = i##

The ##i## in the sum is a "bound variable" or "dummy variable". You could replace it by anything else (except ##n##) without changing the meaning. The ##i## on the right hand side means ##i##.

But using ##i## twice in one equation like that is horrible, as Mark44 said. It would have been more literate to write something like
$$\sum_{k=1}^n A_k = i$$
 

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