Fourier Series with dc offset

Question

I have to obtain Fourier Series of $$ F(x)=x(2\pi-x) $$ for $$ 0 < x < 2\pi $$ $$ f(x) = f(x+2\pi)$$ I am very confused what to do about the last condition: $$ f(x) = f(x+2\pi) $$ my calculated $a(0)$ is $-\frac{2}{3}\pi^2$ and my a(n) term is $ \frac{-2\left(\pi ^2n^2-2\right)\sin \left(\pi n\right)-4\pi n\cos \left(\pi n\right)}{\pi n^3} $ can someone confirm if these are correct?