已知四棱锥P-ABCD中,PA⊥底面ABCD,
,AD=CD=1,∠BAD=120°,
,∠ACB=90°.
(1)求证:BC⊥平面PAC;
(2)求直线PC与平面PAB所成的角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a11029ca6b4b9e7f777af0280cf163c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fd3eb538f36e6e722e4ce125266b99b.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/6/20/244ed6eb-17d8-49af-8ce7-6c123f576b9e.png?resizew=160)
(1)求证:BC⊥平面PAC;
(2)求直线PC与平面PAB所成的角的正弦值.
更新时间:2023-06-17 09:11:39
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【推荐2】如图,在四棱台
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