Find the coefficients $a_n, b_n$ of the Fourier series for the function :
$1 + 5 \sin(3x)+ \cos^2(2x)$
defined on the whole real axis.
I attempted the question, and found that the function could be re-written as:
$\frac {3}{2} + 5 \sin(3x) + \frac {1}{2}\cos(4x)$
I then compared it to the general form of the Fourier series, but my answer was different/wrong.
The answer given for this question (not my attempt) is:
$a_0$ = 3
$a_4$ = $\frac {1}{2}$
$b_3$ = 5
all others are zero.