Cho hbh ABCD. Dựng \(\overrightarrow{AM}\) = \(\overrightarrow{BA}\), \(\overrightarrow{MN}\) = \(\overrightarrow{DA}\), \(\overrightarrow{NP}\) = \(\overrightarrow{DC}\), \(\overrightarrow{PQ}\) = \(\overrightarrow{BC}\). Chứng minh: \(\overrightarrow{AQ}\) = \(\overrightarrow{0}\) .