若<img src="https://zk.995w.com/lqwvjeImg/2e/2e839771ef761aa3e70f4851a47addd7.png"style="width:14px;height:25px;">,<img src="https://zk.995w.com/lqwvjeImg/c3/c38802a93215bca3076161075e0c0a81.png"style="width:14px;height:29px;">为共线的单位向量,则它们的数量积 <img src="https://zk.995w.com/lqwvjeImg/a9/a91bc092edc9fc272a4cce49da19f802.png"style="width:53px;height:29px;">( ).<br>· 1<br>·-1<br>· 0<br>·<img src="https://zk.995w.com/lqwvjeImg/86/863ab2c4a25a15de3ef77a9506c37a23.png"style="width:61px;height:32px;">