Cho cấp số nhân \(\left(u_n\right)\) thoả mãn \(\left\{{}\begin{matrix}u_1+u_2+u_3+u_4+u_5=11\\u_1+u_5=\dfrac{82}{11}\end{matrix}\right.\). Tính S2011.
\(\dfrac{243}{22}\left(1-\dfrac{1}{3^{2011}}\right)\).\(\dfrac{1}{22}\left(3^{2011}-1\right)\).\(\dfrac{243}{22}\left(1-\dfrac{1}{3^{2011}}\right)\) hoặc \(\dfrac{1}{22}\left(3^{2011}-1\right)\).Một đáp số khác.