Fourier Analysis: Calculating 2nd Harmonic

[gaz1984]

All, I'm having some problems with a Fourier analysis I am doing as a coursework, we have been given waves with multiple functions to try and work out the harmonics of them.
My three functions are:
f1 = -5sin (2*pi*t) - sin wave part
f2 = 21.74t-32.61 - straight line part
f3 = 0 - horizontal straight line part

I have worked out A0 using MATLAB and then manually to check the answer.

My problem is that I need to pick a certain harmonic to work out manually to check the MATLAB answer with, i picked the 2nd harmonic.

To work out A2 i get the equations:

1/pi (-5sin(2*pi*t)cos(4*pi*t)) when 0.73 < t < 1.27
1/pi (21.74t*cos(4*pi*t)-32.61cos(4*pi*t)) when 1.27 < t < 1.5

Can anyone help with what I am supposed to do next?
Thanks

 

[rude man]

Is your total wave f1*f2*f3? If so, do f2 and f3 repeat every period (= 1.0s)?