Fourier Series Calculator

Welcome to our Fourier series calculator, an advanced tool designed to swiftly calculate Fourier coefficients for periodic functions.

Please wait... loading-icon

Table of Contents:

Introduction to Fourier Series Calculator:

Fourier series calculator is a tool that is used to compute the Fourier series function coefficient value within the given time domain. It helps to simplify the complex and lengthy process of Fourier series periodic function in a few seconds.

Fourier Series Calculator with Steps

It is the best online source which provides you with complex Fourier series solutions without taking any manual instruction because it has an up-to-date server that allows it to solve all types of complicated problems of Fourier series functions in just one click.

What is the Fourier Series?

Fourier series is a mathematical process used to find a periodic function that is the sum of sine and cosine functions in complex analysis. It was developed by French mathematician Joseph Fourier in the early 19th century.

Fourier transforms to extend their application from non-periodic functions in understanding the frequency and harmonic components of periodic phenomena. It is widely used in various fields like signal processing, image analysis, physics, and engineering to analyze and synthesize periodic signals.

Formula of Fourier Series:

The given function f(x) denotes the function of the Fourier series with the period of time T.

$$ f(x) \;=\; \frac{a_0}{2} + \sum_{n=1}^{\infty} \left[ a_n cos \left(\frac{2n \pi x}{T} \right) + b_n sin \left(\frac{2n \pi x}{T} \right) \right] $$

Here,

a0,an ,bn is the coefficient of Fourier series function and sine or cosine are trigonometric functions of T.

How to Calculate Fourier Series?

To calculate the Fourier series of a periodic function you need to find the value of a0,an and bn because these cofficentes values have their own formulas. Its solution depends on whether you are solving for a continuous or discrete function. Here are the general steps for calculating a Fourier series for a continuous periodic function f(x).

Step 1: Identify the period T of the function f(x) the specific interval value. This is the interval over which the function repeats itself.

Step 2: Compute a0 with the help of formula and add the given values in the given integral function f(x). Here L and -L are the upper and the lower limit. $$ a_0 \;=\; \frac{1}{2L} \int_{-L}^{L} f(x) dx $$

Step 3: Calculate a value by putting the given function value in the below formula. The value of n varies. For n=1,2,3,… $$ a_n \;=\; \frac{1}{L} \int_{-L}^{L} f(x) cos \frac{n \pi x}{L} dx $$

These integrals (or sums for discrete signals) compute the coefficients of the cosine and sine in the Fourier series.

Step 4: For bn repeat the above same procedure of finding the value of bn with its formula that is shown below. $$ b_n \;=\; \frac{1}{L} \int_{-L}^{L} f(x) sin \frac{n \pi x}{L} dx,\; n ≥ 1 $$

Step 5: In the Fourier Series function formula, add all the coefficient values a0,a1, and bn so that you get the solution of Fourier series periodic function. $$ F(x) \;=\; a_0 + \sum_{n=1}^{\infty} \left( a_n cos \frac{n \pi x}{L} + b_n sin \frac{n \pi x}{L} \right) $$

For those who prefer not to manually calculate, We offer a fourier series calculator to quickly calculate the fourier series function coefficient within a given time domain.

Solved Example of Fourier Series:

The solved example of the fourier series in steps will give you an idea about how this fourier sine series calculator solves problems in calculation.

Example: Find the fourier series of following:

$$ f(x) \;=\; x^2 - x \;on\; [-2,2] $$

Determine its sum for -2 ≤ x ≤ 2.

Solution:

$$ f(x) \;=\; x^2 - x $$

$$ L \;=\; 2,\; -L \;=\; -2 $$

The Fourier series function is,

$$ F(x) \;=\; a_0 + \sum_{n=1}^{\infty} \left(a_n cos \frac{n \pi x}{L} + b_n sin \frac{n \pi x}{L} \right) $$

Find the coefficient value of a0, an and bn with the help of their respective formula such as, for a0 value:

$$ a_0 \;=\; \frac{1}{2L} \int_{-L}^{L} f(x)\; dx $$

Put the given value and solve it.

$$ a_0 \;=\; \frac{1}{4} \int_{-2}^{2} (x^2 - x) dx $$

$$ a_0 \;=\; \frac{1}{2} \int_0^2 x^2 dx \;=\; \frac{x^3}{6} \biggr|_0^2 \;=\; \frac{4}{3} $$

For an value:

$$ a_n \;=\; \frac{1}{L} \int_{-L}^{L} f(x) cos \frac{n \pi x}{L} dx $$

Put the given value and solve it.

$$ a_n \;=\; \frac{1}{2} \int_{-2}^{2} (x^2 - x) cos \frac{n \pi x}{2}\; dx,\; n \;=\; 1,2,3,... $$

$$ a_n \;=\; \int_0^2 x^2 cos \frac{n \pi x}{2} dx \;=\; \frac{2}{n \pi} [x^2 sin \frac{n \pi x}{2} \biggr|_0^2 - 2 \int_0^2 x sin \frac{n \pi x}{2} dx] $$

$$ =\; \frac{8}{n^2 \pi^2} [x\; cos \frac{n \pi x}{2} \biggr|_0^2 - \int_0^2 cos \frac{n \pi x}{2} dx] $$

$$ =\; \frac{8}{n^2 \pi^2} \left[2 cos\; n \pi - \frac{2}{n \pi} sin \frac{n \pi x}{2} \biggr|_0^2 \right] \;=\; (-1)^n \frac{16}{n^2 \pi^2} $$

For bn value:

$$ b_n \;=\; \frac{1}{L} \int_{-L}{L} f(x) sin \frac{n \pi x}{L} dx, n ≥ 1 $$

Put the given value and solve it.

$$ b_n \;=\; \frac{1}{2} \int_{-2}^{2} (x^2 - x) sin \frac{n \pi x}{2} dx,\; n \;=\; 1,2,3,... $$

$$ b_n \;=\; -\int_0^2 xsin \frac{n \pi x}{2}dx \;=\; \frac{2}{n \pi} \left[ x\; cos \frac{n \pi x}{2} \biggr|_0^2 - \int_0^2 cos \frac{n \pi x}{2} dx \right] $$

$$=\; \frac{2}{n \pi} \left[ 2 cos n \pi - \frac{2}{n \pi} sin \frac{n \pi x}{2} \biggr|_0^2 \right] \;=\; (-1)^n \frac{4}{n \pi} $$

Add the value of a0, an, and bn in the Fourier series formula and you get the solution of the Fourier series function.

$$ F(x) \;=\; \frac{4}{3} + \frac{16}{\pi^2} \sum_{n=1}^{\infty} \frac{(-1)^n}{n^2} cos \frac{n \pi x}{2} + \frac{4}{\pi} \sum_{n=1}^{\infty} \frac{(-1)^n}{n} sin \frac{n \pi x}{2} $$

How to Use the Fourier Cosine Series Calculator?

The Fourier series coefficients calculator has a simple design that makes it easy for you to know how to use it for the evaluation of Fourier series problems. Follow our instructions which are given as:

  • Enter the given Fourier series function that you want to evaluate in the given input field.
  • Check the given complex Fourier series function before clicking the calculate button to start the evaluation process in the Fourier series coefficient calculator.
  • Click the “Calculate” button to get the result of your given Fourier series function problem.
  • If you are trying our Fourier series expansion calculator for the first time then you can use the load example to learn more about this concept.
  • Click on the “Recalculate” button to get a new page for finding more example solutions to Fourier series problems.

Output of Fourier Series Piecewise Calculator:

The fourier series calculator gives you the solution from a given function when you add the input into it. It included as:

  • Result Option:

When you click on the result option, it gives you a solution to the Fourier series function to find its solution.

  • Possible Steps:

When you click on it, this option will provide you with a solution where the calculation process of the Fourier series is mentioned.

  • Plot option:

It will give you a graphical representation of Fourier series function solutions to get a better understanding of graphs.

Useful Features of Fourier Sine Series Calculator:

The Fourier cosine series calculator provides you with tons of useful features that help you to calculate the fourier series of given function problems and give you solutions without any trouble. These useful features are:

  • Fourier series coefficients calculator is a free-of-cost tool so you can use it for free to find fourier series problems with solutions without spending.
  • It gives you conceptual clarity for the fourier series process when you use it for practice to solve more examples.
  • The fourier series coefficient calculator saves the time and effort that you consume on the calculation of complex functions for finding the fourier series problems manually.
  • It is an adaptable tool that provides you with precise solutions whenever you use it to calculate fourier series function without any man-made mistakes in calculation.
  • Fourier series expansion calculator enables you to use it multiple times for the evaluation of fourier series problems.
  • Fourier series piecewise calculator is a handy tool because you can access it through an online platform from anywhere.
Related References
Frequently Ask Questions

Can any function be represented as a fourier series

Yes, any periodic function with a well-defined period can be represented as a Fourier series. It does not mean every function can be represented as a Fourier series because it has some criteria that need to be followed for the Fourier series. A function that does not meet these criteria, particularly non-periodic or non-integrable functions condition cannot be represented by a Fourier series.

How to tell if fourier series is odd or even

Fourier series is an odd, even function but its even or odd series does not depend on the properties of the function f(x). Here’s how you can classify the Fourier series based on the symmetry of f(x):

Odd Fourier Series

A Fourier series is odd if the function f(x) satisfies the following symmetry:

$$ f(−x) \;=\; −f(x) $$

In other words, f(x)is symmetric about the origin, and its value at −x is the negative of its value at x.

Steps to Determine if the Fourier Series is Odd:

  1. Compute a0 and if a0 = 0, because the positive and negative areas cancel each other over one period.
  2. Compute an and bn to find the Fourier coefficients for cosine and sine terms
    For an odd function, an = 0 (no cosine terms) and bn ≠ 0(non-zero sine terms).
  3. Check f(x)Symmetry and verify the function f(−x) = −f(x) holds the condition for the function f(x)

Even Fourier Series

A Fourier series is even if the function f(x) satisfies the symmetry condition:

$$ f(−x) \;=\; f(x) $$

In this case, f(x) is symmetric about the y-axis.

Steps to Determine if the Fourier Series is Even:

  1. Compute a0 then the average value of f(x) over one period: a0=1. For an even function, a0 represents the average value of f(x)around the y-axis.
  2. Compute an and bn to calculate the Fourier coefficients
    For an even function, bn = 0 (no sine terms) and an ≠ 0 (non-zero cosine terms).
  3. Check f(x)Symmetry and verify that f(−x) = f(x) holds the condition for the function f(x).

What is the difference between fourier series and fourier transform

Fourier series and the Fourier transform are both different methods used for analyzing functions, especially in terms of their frequency components. However, they are used in different contexts and have distinct forms.

Fourier Series

The Fourier series represents a periodic function as a sum of sine and cosine functions with different frequencies. It is particularly useful for analyzing periodic signals.

For a periodic function f(t) with period T, the Fourier series is given by:

$$ f(t) \;=\; a_0 + \sum_{n=1}^∞ (an\; cos (\frac{2πnt}{T}) + b_n sin (\frac{2πnt}{T})) $$

Fourier Transform

The Fourier transform is used to transform a non-periodic (or periodic) function from the time domain to the frequency domain. It is useful for analyzing signals over all frequencies in a continuous spectrum.

$$ f(t) \;=\; \frac{1}{2π} \int_{- ∞}^∞ F(ω) e^{iωt} dω $$

Both the Fourier series and Fourier transform decompose functions into their frequency component but the Fourier series is used for periodic functions with discrete harmonics, and the Fourier transform is used for continuous function spectrum of frequencies.

Why is fourier series important

The Fourier series is important for several purposes, especially n the fields of mathematics, engineering, and physics for analyzing and synthesizing periodic functions such as in signal processing, acoustics, electrical engineering, and more.

  1. Decomposition of Periodic Signals
  2. Signal Processing
  3. Simplification of Complex Problems
  4. Orthogonality of Basis Functions
  5. Application in Electrical Engineering
  6. Vibration Analysis and Acoustics

What is a0 in fourier series

Fourier series, a0 represents the average value or the direct current component of the periodic function when it is analyzed. It is the coefficient of the harmonic function in the Fourier series expansion and represents the mean value of that function over one period. It plays a crucial role in determining the even or odd function in Fourier series. Its formula is,

$$ a_0 \;=\; \frac{1}{T} \int_0^T f(t) dt $$

Is This Tool Helpful