Дано: ABCD - параллелограмм, \(BM = MC\), \(\overrightarrow{a} = \overrightarrow{AB}\), \(\overrightarrow{b} = \overrightarrow{AD}\), \(\overrightarrow{c} = \overrightarrow{MD}\).
Найти: \(\overrightarrow{c}\).
Решение:
\(\overrightarrow{MD} = \overrightarrow{MC} + \overrightarrow{CD} = \frac{1}{2} \overrightarrow{BC} - \overrightarrow{AB} = \frac{1}{2} \overrightarrow{AD} - \overrightarrow{AB} = \frac{1}{2} \overrightarrow{b} - \overrightarrow{a}\).
Ответ: \(\frac{1}{2} \overrightarrow{b} - \overrightarrow{a}\)