# Fourier coeffs of a function in Matlab

1. Apr 14, 2009

### Alexandr

I have a harmonic function which is a product of cosines (something with many cos(k*phi)) and it can be represented as a finite series with only cos terms... We know it...

Now. Every step we multiply this function by one more cos and want to find the Fourier coefs.

So, I don't understand two things...
1. There is no any method in Matlab to generate functions of variables as I understand... So, how can I provide this updating? I need that function of phi...
2. Is there any command for finding nth Fourier coefficient of function, not a vector?

Any useful tips?

2. Apr 14, 2009

### Dr Transport

If you can write the function, set a vector of points x where the delta is very small, evaluate the function then take the FFT, the coefficients should pop right out as the real part.