# Homework Help: Fourier Coefficients

1. Mar 27, 2009

### Nusc

1. The problem statement, all variables and given/known data

f(t) = 1 0<=t<T/2
-1 T/2 <=t<=T

ie. step function.

frequency w_0 = 2pi/T

2. Relevant equations

3. The attempt at a solution

What's the definition for the fourier coefficients a_n and b_n again? Not the one in wikipedia.

2. Mar 27, 2009

### Dr.D

Show us the work you have done on this. There are defining integrals for these coefficients, so set them up and try evaluating them.

3. Mar 28, 2009

### Nusc

$$a_n = \frac{1}{\pi} \int_0^{T/2} 1*cos(nt) dt +\frac{1}{\pi} \int_{T/2}^{T} (-1)*cos(nt) dt$$

$$b_n = \frac{1}{\pi} \int_0^{T/2} 1*sin(nt) dt +\frac{1}{\pi} \int_{T/2}^{T} (-1)*sin(nt) dt$$

I think the normalization factor is incorrect, which is why i asked for the definition, I think it was 2/L where L is the length of the interval - i can't remember.

4. Mar 28, 2009

### Dr.D

If you can't remember, do you have a book?

5. Mar 28, 2009