Fourier Series for Periodic Functions - Self Study Problem

Gopal Mailpalli
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Self Study
1. Homework Statement

Consider a periodic function f (x), with periodicity 2π,
h3YE5bX.jpg

Homework Equations


##A_{0} = \frac{2}{L}\int_{X_{o}}^{X_{o}+L}f(x)dx##
##A_{n} = \frac{2}{L}\int_{X_{o}}^{X_{o}+L}f(x)cos\frac{2\pi rx}{L}dx##
##B_{n} = \frac{2}{L}\int_{X_{o}}^{X_{o}+L}f(x)sin\frac{2\pi rx}{L}dx##

The Attempt at a Solution


##A_{0} = C##
##A_{n} = 0##
##B_{n} = \frac{-C}{\pi r}cos\pi r##
http://imgur.com/a/4Q2oL
 
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Gopal Mailpalli said:
Self Study
1. Homework Statement

Consider a periodic function f (x), with periodicity 2π,
h3YE5bX.jpg

Homework Equations


##A_{0} = \frac{2}{L}\int_{X_{o}}^{X_{o}+L}f(x)dx##
##A_{n} = \frac{2}{L}\int_{X_{o}}^{X_{o}+L}f(x)cos\frac{2\pi rx}{L}dx##
##B_{n} = \frac{2}{L}\int_{X_{o}}^{X_{o}+L}f(x)sin\frac{2\pi rx}{L}dx##

The Attempt at a Solution


##A_{0} = C##
##A_{n} = 0##
##B_{n} = \frac{-C}{\pi r}cos\pi r##
http://imgur.com/a/4Q2oL
This post should have been sent to Calculus and Beyond Forum.

Your picture is hardly readable. Better to type the text in, or write it clearly and make a better picture.
The formula for the b coefficients is not correct. What happens in case of even index? What is b2, for example?
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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