Fourier Cosine Series: Equivalence for {x}

In summary, Fourier series integral transform notes state that the correspondence between the Fourier cosine series and the function f (x) = x, o < x < Pie is actually an equality for 0 ≤ x ≤ Pie.
  • #1
Joystar77
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2. Fourier cosine series correspondence for f(x)= x, o < x < pi given by x ~ pi / 2 - 4/n, E infinity on top and n=1 on bottom. cos (an-1)/x / (2n-1)squared, (0 < x < pi).

Explain why this correspondence is actually an equality for 0 is less than or equal to x and x is less than or equal to pi. Then explain how we can write

{x} = pi /2 - 4 / n E infinity on top and n=1 on bottom

cos (2n - 1)x/ (2n-1) squared, (-n is less than or equal to x and x is less than or equal to pi)
 
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  • #2
Sorry, I forgot to mention in the original thread that I am totally lost and don't know where to start at with this problem.
 
  • #3
Here is the above problem and I hope that its easier to read. I used some Mathematical symbols, so hope that you can understand it. Any questions, then please ask me if your unable to understand or read the problem.

Fourier cosine series correspondence for f (x) = x, o < x < Pie given by x ~ Pie / 2 – 4 / n

∑_(n=1)^∞▒cos⁡〖(2n-1)x/(2n-1)〗 〖^2〗,(o<x<Pie)

Explain why this correspondence is actually an equality for 0 ≤ x ≤ Pie. Then explain how we can write

[x] = Pie / 2 – 4 / n ∑_(n=1)^∞▒cos⁡〖(2n-1)x/(2n-1)〗 〖^2〗 ( -n ≤ x ≤ Pie)
 
  • #4
Joystar1977 said:
Here is the above problem and I hope that its easier to read. I used some Mathematical symbols, so hope that you can understand it. Any questions, then please ask me if your unable to understand or read the problem.

Fourier cosine series correspondence for f (x) = x, o < x < Pie given by x ~ Pie / 2 – 4 / n

∑_(n=1)^∞▒cos⁡〖(2n-1)x/(2n-1)〗 〖^2〗,(o<x<Pie)

Explain why this correspondence is actually an equality for 0 ≤ x ≤ Pie. Then explain how we can write

[x] = Pie / 2 – 4 / n ∑_(n=1)^∞▒cos⁡〖(2n-1)x/(2n-1)〗 〖^2〗 ( -n ≤ x ≤ Pie)
http://mathhelpboards.com/math-notes-49/fourier-series-integral-transform-notes-2860.html
 
  • #5
Thanks! I will take a look at these Fourier Series Integral Transform Notes.

dwsmith said:
http://mathhelpboards.com/math-notes-49/fourier-series-integral-transform-notes-2860.html
 

FAQ: Fourier Cosine Series: Equivalence for {x}

What is a Fourier cosine series?

A Fourier cosine series is a mathematical representation of a function using a series of cosine terms. It is a way to express a periodic function as a sum of simpler cosine functions.

How is a Fourier cosine series different from a Fourier series?

A Fourier cosine series only uses cosine terms, while a Fourier series can use both sine and cosine terms. This means that a Fourier cosine series is only applicable to even functions, while a Fourier series can be used for both even and odd functions.

What is the equivalence for {x} in a Fourier cosine series?

The equivalence for {x} in a Fourier cosine series refers to the concept that a function and its Fourier cosine series have the same value at any given point x. This means that the Fourier cosine series is an accurate representation of the original function.

How is the equivalence for {x} proven?

The equivalence for {x} is proven using mathematical techniques such as the Dirichlet conditions and the Fourier cosine series convergence theorem. These techniques show that as the number of terms in the cosine series increases, the series approaches the original function in terms of accuracy.

What are some applications of Fourier cosine series?

Fourier cosine series are widely used in fields such as signal processing, image processing, and physics. They are used to analyze and manipulate periodic functions and can also be used to solve differential equations. Additionally, they are useful in approximating non-periodic functions by creating a periodic extension of the function.

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