(2014?陕西三模)如图所示,在直三菱柱ABC-A1B1C1中,CA⊥CB,CA=CB=1,AA1=2,且N是棱A1B
(2014?陕西三模)如图所示,在直三菱柱ABC-A1B1C1中,CA⊥CB,CA=CB=1,AA1=2,且N是棱A1B1的中点,(Ⅰ
![](https://img.yulucn.com/upload/d/de/dde06cf22546f8ea50b88aa81245ba6a_thumb.jpg)
(2014?陕西三模)如图所示,在直三菱柱ABC-A
1B
1C
1中,CA⊥CB,CA=CB=1,AA
1=2,且N是棱A
1B
1的中点,
(Ⅰ)求证:A
1B⊥C
1N;
(Ⅱ)求直线A
1B和直线B
1C夹角的余弦值.