Discover the Fourier Series of (sin x)^2 with Helpful Tips!

In summary, the conversation discusses finding the Fourier series of the function (sin x)^2 and whether or not integration is needed for the problem. It is suggested to use double angle formulas and trig identities to simplify the problem and compute the coefficients of the Fourier series. It is also mentioned that the Fourier series consists of functions of the form cos(nx) and sin(nx).
  • #1
calcgirl
2
0
fourier series, please help!

Homework Statement


Find the Fourier series of f(x)=(sin x)^2.

Homework Equations





The Attempt at a Solution



I know that I need to use the double angle formulas for this problem:
(sin x)^2=1/2-1/2(cos 2x)
but I do not know where to go from here.
 
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  • #2
All you have to do is calculate the coefficients of the Fourier series... which boils down to computing an integral. See your notes.
 
  • #3
I was told that no integration was needed for this problem and it basically boils down to trig identities.
 
  • #4
Do you know what the Fourier Series is for cos(x)? I'd imagine you could just do you substitution and then use Fourier tables and the like to make that entire thing a Fourier series.
 
  • #5
calcgirl said:
I was told that no integration was needed for this problem and it basically boils down to trig identities.

When you used the trig identity you have already written down the cosine series. It has a cos(0*x) term and a cos(2*x) term. What are the coefficients? That IS a Fourier series. Do you want it in some other form?
 
  • #6
Definitely no integration is needed for this problem. Do you understand what a Fourier series is? It is a sum of functions of the form cos(nx) and sin(nx)! What is the Taylor's series, about x= 1 for (x-1)2? What is the Fourier seiries for cos(x)? What is the Fourier series for sin(2x)?
 

Related to Discover the Fourier Series of (sin x)^2 with Helpful Tips!

What is a Fourier Series?

A Fourier Series is a way to represent a periodic function as a sum of sine and cosine functions with different amplitudes and frequencies.

What is the formula for the Fourier Series?

The formula for the Fourier Series of a function f(x) is given by:
f(x) = a0 + ∑n=1 [ancos(nx) + bnsin(nx)],
where a0, an, and bn are the coefficients that determine the amplitude and frequency of the sine and cosine functions.

How do I find the coefficients for a Fourier Series?

To find the coefficients for a Fourier Series, you need to use the following formulas:
an = (1/π) ∫π f(x)cos(nx)dx,
bn = (1/π) ∫π f(x)sin(nx)dx.

What are some tips for finding the Fourier Series of (sin x)^2?

Some helpful tips for finding the Fourier Series of (sin x)^2 are:
1. Rewrite (sin x)^2 as (1/2)[1-cos(2x)].
2. Use the formulas for an and bn to find the coefficients.
3. Keep in mind that the series will only have odd terms since the function is an odd function.
4. Simplify the series by using trigonometric identities.

Why is the Fourier Series important in science?

The Fourier Series is important in science because it allows us to analyze and understand complex periodic functions by breaking them down into simpler components. It has applications in various fields such as signal processing, image and sound compression, and solving differential equations. It also helps in approximating functions and can provide insights into the behavior of physical systems.

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