One fundamental property of Fourier Series

In summary, a Fourier Series is a mathematical representation of a periodic function as a sum of sinusoidal functions with different frequencies and amplitudes. Its fundamental property is that any periodic function can be represented as a sum of sinusoidal functions, making it easier to analyze and understand. It is calculated using a formula that involves finding coefficients through integration, and has numerous applications in science and engineering. However, it can only be used for periodic functions with a finite number of discontinuities and its accuracy depends on the number of terms used.
  • #1
viczhang
2
0
Suppose the functions f(t) and g(t) are periodic with periods P and Q, respectively. If the ratio P/Q of their periods is a rational number, show that the sum f(t)+g(t) is a period function.

How to prove this?
 
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  • #2
If their ratio is a rational number, it means it can be represented as:

[tex]
\frac{P}{Q} = \frac{m}{n}, \; m, n \in \mathbb{Z}^{+}, \; \mathrm{GCD}(m, n) = 1
[/tex]

Now, consider an interval of length:

[tex]
R = \frac{P}{m}*\mathrm{LCM}(m, n)
[/tex]

What can you say about [itex]f(x + R)[/itex] and [itex]g(x + R)[/itex]?
 

1. What is a Fourier Series?

A Fourier Series is a mathematical representation of a periodic function as a sum of sinusoidal functions with different frequencies and amplitudes. It is named after French mathematician Joseph Fourier and is commonly used to analyze and approximate complex signals and functions.

2. What is the fundamental property of a Fourier Series?

The fundamental property of a Fourier Series is that any periodic function can be represented as a sum of sinusoidal functions. This means that any periodic function can be broken down into simpler components, making it easier to analyze and understand.

3. How is a Fourier Series calculated?

A Fourier Series is calculated using a mathematical formula called the Fourier Series formula. This formula involves finding the coefficients of the sinusoidal functions by integrating the periodic function over one period. These coefficients are then used to construct the Fourier Series representation of the function.

4. What is the significance of Fourier Series in science and engineering?

Fourier Series have numerous applications in science and engineering. They are used to analyze and approximate signals in fields such as telecommunications, audio and image processing, and geophysics. They are also used in solving differential equations and studying the behavior of physical systems.

5. Are there any limitations to using Fourier Series?

While Fourier Series are a powerful tool, they do have some limitations. They can only be used for periodic functions, and the function must have a finite number of discontinuities within one period. Additionally, the accuracy of the Fourier Series approximation depends on the number of terms used in the series, so it may not be suitable for highly complex functions.

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