摘要:17. 直四棱柱ABCD-A1B1C1D1中.∠ADC = 90°.△ABC为等边三角形.且AA1 = AD = DC= 2 . (Ⅰ)求异面直线AC1与BC所成的角余弦值, (Ⅱ)求证:BD⊥平面AC1, (Ⅲ)求二面角B-AC1-C的正切值.

网址:http://m.1010jiajiao.com/timu_id_3040912[举报]

违法和不良信息举报电话:027-86699610 举报邮箱:58377363@163.com

精英家教网