如果是向量的话,
3AB+2BC+CA=2AD
3AB+2BC+CA
=2AB+BC+(AB+BC+CA)
=2AB+BC+0
∵D是BC中点
∴BC=2BD
2AB+BC
=2AB+2BD
=2(AB+BD)
=2AD
请及时点击右下角的【满意】按钮