‎给定向量<img src="https://static.zxtiku.com/wangke/imgs/topic/f6febc179f66d0ca48e036c0df1f934b.png"/>与向量<img src="https://static.zxtiku.com/wangke/imgs/topic/475b088e0d50ec4967a5f9e2e3873cc0.png"/>, 计算<img src="https://static.zxtiku.com/wangke/imgs/topic/dc67dab8505ee0ef14ce45de826b7955.png"/>___________.