Showing fourier series of sin^2(x)=(1/2)-(cos(2x)/2)

In summary, a Fourier series is a mathematical representation of a periodic function using sine and cosine functions. To calculate the series, coefficients for each term can be found through integration or using the Fourier series formula. The Fourier series of sin^2(x) is (1/2) - (cos(2x)/2) and it can be used to recreate the original function. Knowing the Fourier series of a function is useful for analyzing and understanding complex functions, as well as in various fields such as signal processing, engineering, and physics.
  • #1
charity4thep
4
0

Homework Statement



f(x)=sin^2(x)

Homework Equations





The Attempt at a Solution



solving for a(0)= i did (1/2Pi)*int(sin^2(x),x,-Pi..Pi)=1/2
b(n)=0 because sin^2(x) is an even function
a(n)=(1/Pi)*int(sin^2(x)cos(n*x),x,-Pi..Pi)=1/2Pi((sin(xn)/n)-(.5sin((2-n)x)/(2-n))-(.5sin((2+n)x)/(2+n))) this whole thing evaluated from -Pi..Pi

I keep getting zero although I know this is not the answer, so maybe I am messing up somewhere. Help is greatly appreciated.
 
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  • #2
Make sure you're not dividing by zero.
 

1. What is a Fourier series?

A Fourier series is a mathematical representation of a periodic function as a combination of sine and cosine functions. It allows us to break down a complex function into simpler components.

2. How do I calculate the Fourier series of a function?

To calculate the Fourier series of a function, you need to find the coefficients for each sine and cosine term using integration. For a periodic function, the coefficients can be found using the Fourier series formula.

3. What is the Fourier series of sin^2(x)?

The Fourier series of sin^2(x) is (1/2) - (cos(2x)/2). This can be derived by using the trigonometric identity sin^2(x) = (1-cos(2x))/2 and applying the Fourier series formula.

4. How does the Fourier series of sin^2(x) relate to the original function?

The Fourier series of sin^2(x) is a representation of the original function as a combination of sine and cosine functions. By adding up all the terms in the series, we can recreate the original function.

5. Why is it useful to know the Fourier series of a function?

The Fourier series allows us to break down a complex function into simpler components, making it easier to analyze and understand. It is also used in various fields such as signal processing, engineering, and physics to model and manipulate periodic functions.

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