Chrome，
QQ浏览器
.
![人教A高中数学必修四2.4.1 平面向量数量积的物理背景及其含义[王丽娜]【市一等奖】优质课](http://imgshow.1ydt.com/img?url=%2F%2Fi2.hdslb.com%2Fbfs%2Farchive%2Fef3ec3fcc83f42203339af1a9ec2d6569c74d6bc.jpg%40672w_378h_1c_%21web-search-common-cover)
![[高数下册1]向量的数量积，向量积，混合积](http://imgshow.1ydt.com/img?url=%2F%2Fi1.hdslb.com%2Fbfs%2Farchive%2Fb0111a235cfc24f0a9cee6dcc7eb576b6ce1a5c0.jpg%40672w_378h_1c_%21web-search-common-cover)
![三角形的四心与平面向量，学会这些，得分轻而易举[高一春季3]](http://imgshow.1ydt.com/img?url=%2F%2Fi0.hdslb.com%2Fbfs%2Farchive%2F572a09145d72f54f91c7094ba237ace7e189c670.jpg%40672w_378h_1c_%21web-search-common-cover)
.