Introduction to Fourier series
 
Purpose
Review fourier series background knowledge.
 
Table of contents


Euler's formula

Euler’s formula is an important basis for fourier series (as we should see in following homeworks). Here the definition of Euler’s formula is given.
 
 

Euler’s formula

is reached by combining the results of the taylor series for e to a complex number, sin(x) and cos(y).

The Taylor series at x=a is defined below and is a polynomial estimation of the given function. When a=0 the series is called a Maclaurin series. A graphical illustration of the taylor series of sin can be found here: http://math.furman.edu/~dcs/java/taylor.html (requires java) :

This means that e to a complex number equals the following for the Maclaurin series. See how the components group into a real and imaginary component.

The Maclaurin series of cos at results in:

Use the following fact and that cos(0)=1 and sin(0)=0





The Maclaurin series results in:

Substituting the Maclaurin series of cos() and sin() into the series for e gives the result we were looking for:





Euler's formula with powers

 

Dealing with powers and Euler’s formula given above, the following is true.


 
Solution

Evaluating the folowing is done with referencing a trigonometry page like http://www.ping.be/~ping1339/gonio.htm#Sum-formulas



 
 


 
 
 
 
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dorian miller, 8/16/2000