如图,在正四棱柱
中,
,
,E,M,N分别是
,
,
的中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/e951367c-7767-436a-8a1d-3463722e4f16.png?resizew=155)
(1)求三棱锥
的体积;
(2)求异面直线
与
所成角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e55a2310cbba5e050488cd9296eb195d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd0ced286a0fbc7e4862f8147264277.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0a851907ada2ac2c3c4880a6736d28a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10d8eb4a9f462ca0c1d49c3fe91e720d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/12/e951367c-7767-436a-8a1d-3463722e4f16.png?resizew=155)
(1)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08e4269ebbbcfbd50306e44ff1c691b6.png)
(2)求异面直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411461db15ee8086332c531e086c40c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/93ecad355286188fd317939fa50f9555.png)
更新时间:2021-02-05 20:27:57
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d20e38a1b5cfffd43a3405481a1d67cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
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![](https://img.xkw.com/dksih/QBM/2016/9/20/1573031639203840/1573031645618176/STEM/d317196b04cc4987896cf62d5e6ca9cc.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0149a639635b31717ddad7dfec0a63c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ffe8a84ca3a13f82aff1a022edc66065.png)
(2)求三棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05ccce05caa88496e5bd9f9a3a0f5552.png)
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![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/26/5c3e6154-6d80-4b7b-9415-8147ce5ec61a.png?resizew=169)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39282bdf319f30d7bc261e2e3ab3b1e4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3df5935c893580c77ab6fa6eb0a70bdb.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0bf9718967af7a01c5b4866ea6f73bbb.png)
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【推荐3】如图,正三棱柱
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