$F=(9x+7\pi)$, given period $[-\pi;\pi)$. Find Fourier series for the given function if $x=-\pi$.
Firstly I found $a_0$ which was equal to $7\pi$ and $a_k$ and $b_k$ were equal to $0$. So I found if $x=-\pi$; Fourier series equal to $7\pi$.
Also given answers:
a) $-2\pi$
b) $6\pi$
c) $7\pi$
d) $9\pi$
e) Not of the above
I chose $7\pi$. Is it correct or not?
The coefficients you give are not good. You actually computed those of the constant function equal to $7\pi$ while the considered function is $x\mapsto 9x+7\pi$.