Are _potatoes? [ ] A. this B. those C. 发布时间:2017-03-20 22:12 │ 来源:www.tikuol.com 题型:选择题 问题: Are _ potatoes? [ ]A. this B. thoseC. that
题型:选择题 设a,b,c是任意的非零平面向量,且相互不共线,则下列命题中,真命题的序号是( )①(a•b)c-(c•a)b=0 ②丨a|-|b|<丨a-b丨③(b•c)a-(c•a)b不与c垂直④(3a+2b)•(3a-2b)=9|a|2-4|b|2.A.①②B.②③C.③④D.②④ 查看答案