平面a过正方体ABCD-A1B1C1D1的顶点A,a//平面CB1D1,a∩平面AB 发布时间:2017-06-02 01:38 │ 来源:www.tikuol.com 题型:单项选择题 问题: 平面a过正方体ABCD-A1B1C1D1的顶点A,a//平面CB1D1,a∩平面ABCD=m,a∩平面ABB1A1=n,则m、n所成角的正弦值为()。A.AB.BC.CD.D
题型:单项选择题 __________ is known to us all that the earth is smaller than the sun. [ ]A. What B. As C. Which D.It 查看答案