如图,直角梯形
中,
,等腰梯形
中,
,且平面
平面
.
(1)求证:
平面
;
(2)若
与平面
所成角为
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ac66de8543430fd51e7c18042e626dd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b84108812549556327dc648bc4330115.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d747629ff8da4a33896df9a163c3940d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ed9c7b69462dc9226e35ddac8f179cf0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e56fdf217165748fafe938b64fa08179.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4ac66de8543430fd51e7c18042e626dd.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/274cf35acb4a1748d15c39d15a9bea7b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af9955b5aebb73cd84447e8541f901ac.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21b8c75b0e52a073e9271ed93465b861.png)
![](https://img.xkw.com/dksih/QBM/2018/2/25/1890158496743424/1893434390183936/STEM/137ef8b2fe6146ffba9fa1a4f95eea0a.png?resizew=196)
更新时间:2018-03-02 13:05:02
|
相似题推荐
解答题-问答题
|
适中
(0.65)
名校
【推荐1】如图,在四棱锥
中,底面
为菱形,
底面
,
,
为线段
的中点,
为线段
上的动点,平面
平面
.
(1)证明:
;
(2)若
到平面
的距离为1,求
与平面
所成角的最小值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83a04565a8ebaa111894b724b0ba266.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a30f3a8b673cc28bd90c50cf1a35281.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64899adb2cc8913ed7d511eade821422.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3e61111c1e9b98b79615f75540175c9.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/21/47c94ac4-62da-48b1-bfad-a31b927db980.png?resizew=163)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edbf6462666c8015e7de28e344af30b2.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0f85fca60a11e1af2bf50138d0e3fe62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6aa2b5e09f8ec785c59900a529390a02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐2】如图1,在平面四边形PDCB中,
,
,
,
.将
沿BA翻折到
的位置,使得平面
平面ABCD,如图2所示.
![](https://img.xkw.com/dksih/QBM/2022/6/6/2995341171998720/2995764700618752/STEM/d6b594ab-ef6b-4db8-aa95-76ad0e3e2946.png?resizew=464)
(1)设平面SDC与平面SAB的交线为l,求证:BC⊥l;
(2)点Q在线段SC上(点Q不与端点重合),平面QBD与平面BCD夹角的余弦值为
,求线段BQ的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/216e4003cb76fc52b251e38a0afdd202.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a45024b1f1c50249cc194e8689ec01cc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81981fd7b343f4fe2db8f36eb66c1ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3f4aca5534bce25acaeb7379deed8f8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2205cffebf8c4d5f81d15ed7b85c8936.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/72e49817548cb45b3d1e58570644c6fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/448cbac9a1ef3de7538a6b30cdc39582.png)
![](https://img.xkw.com/dksih/QBM/2022/6/6/2995341171998720/2995764700618752/STEM/d6b594ab-ef6b-4db8-aa95-76ad0e3e2946.png?resizew=464)
(1)设平面SDC与平面SAB的交线为l,求证:BC⊥l;
(2)点Q在线段SC上(点Q不与端点重合),平面QBD与平面BCD夹角的余弦值为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/64f1145c162038df3c7184d9201c628e.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
【推荐3】如图,直三棱柱中,
,平面
平面
(1)证明
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1080295895df074480087279a84d7a2a.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1080295895df074480087279a84d7a2a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a5f459a5b72f42693fb7e07a01357400.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3ee8456443402a25b1e25d35ff7e1c98.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
解题方法
【推荐1】已知三棱柱
中,面
底面
,
,底面
是边长为2的等边三角形,
,E、G分别是棱
的三等分点(点E在点G的上方)F在棱
上,且
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/636a4b10-ea78-41cb-9ec2-89b3a0169cfc.png?resizew=130)
(1)求证:![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afd8dfb021c5654dd3bef791065b5c45.png)
(2)在棱
上找一点M,使得
和面
所成角的余弦值为
,并说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71f2185273bf04c11118c7954f7ec822.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2968d1a1690dd7caef51754e1aaa235f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/890b36d4b33ae15010172d7306a07ce1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7bef5239ddbb0972700ce01daf9ee7cf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd21a4e45dc1beb069d7e78f84a51544.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6024fd4532f5f981deac4582c799a6ef.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/20ecac2dad4cffdd971fd23deacff3fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22128296e5f6fac1dc20bf690d35db4c.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/11/29/636a4b10-ea78-41cb-9ec2-89b3a0169cfc.png?resizew=130)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/afd8dfb021c5654dd3bef791065b5c45.png)
(2)在棱
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24cfad1ba71a78d8f415335cde2f8c52.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e69d2b798744645af88a4fa411344a83.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/87c0bfeadcf17b2a45896071f07a4a5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/325a7e0b7ee0ac876b0d64d740f02937.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】如图,四棱锥
的底面是平行四边形,
平面
,
.
![](https://img.xkw.com/dksih/QBM/2022/5/21/2984179082108928/2984789463392256/STEM/c9e9bdc78e1f451e980a0875a1c02c76.png?resizew=189)
(1)证明:平面
平面
;
(2)设平面
平面
,若直线
与平面
所成角为
,求二面角
的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bfdfe3d429b035719c81d245ee4f4842.png)
![](https://img.xkw.com/dksih/QBM/2022/5/21/2984179082108928/2984789463392256/STEM/c9e9bdc78e1f451e980a0875a1c02c76.png?resizew=189)
(1)证明:平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/342d452a7b850cd3a15b23619ad39bd7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0628681907ac8d7fdb94d8bc1b15feb9.png)
(2)设平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c762937111e04018cad6b507a7dedc02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/baceb049bf16ed0fd33639fdda0ec5ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d2be49c37e30a3ced0364c3e74d8c687.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/80f747eb5b2d21c9de962cbfd4ec4bb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f6b86c22b670a8e9f3896f9e8883fbbb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/757b1bff2cbba8ac3cd4304a3b1fe968.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐3】如图所示,在四棱锥
中,
平面ABCD,四边形ABCD是矩形,且
,
,E是棱BC上的动点,F是线段PE的中点.
平面ADF;
(2)若直线DE与平面ADF所成的角为30°,求EC的长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0585b6c0f156eecf9662b9846d4eb693.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ccd4fd4b7a4d6b8ca0c5827c055a9ce7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83a04565a8ebaa111894b724b0ba266.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0d5a2cd05e4476fc72271e8fdb59a9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c45fbffb9e2c7fa7c5006cde8da0cabe.png)
(2)若直线DE与平面ADF所成的角为30°,求EC的长.
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】如图,
,
为圆
的两条直径,
垂直于圆
所在的平面.
![](https://img.xkw.com/dksih/QBM/2022/4/2/2949379147825152/2950385600192512/STEM/5e117d09f5c5412f9bdc4ca4e5e57cd4.png?resizew=186)
(1)证明:
.
(2)若
,
,
,求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/60ef95894ceebaf236170e8832dcf7e3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40b319212a7e7528b053e1c7097e966.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bd33764ff4efddfe11a98a609753715c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1dde8112e8eb968fd042418dd632759e.png)
![](https://img.xkw.com/dksih/QBM/2022/4/2/2949379147825152/2950385600192512/STEM/5e117d09f5c5412f9bdc4ca4e5e57cd4.png?resizew=186)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/da48240e7fc3248f773ac1500c15ec14.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/491c3a4f72b84ebadd28b90711435adc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0c14a66ed4bd66df65bc42c4ac1ed15c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cfc1f76257275ab4b04f9bc913535670.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/852aabd89edffc1b94344ff3f1f31ccd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7b7c83470489253394bd288d7c920df.png)
您最近一年使用:0次
解答题-应用题
|
适中
(0.65)
【推荐2】如图,在直四棱柱
中,底面
是直角梯形,
,
,且
.
平面
;
(2)求平面
与平面
所成锐二面角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e09725691ee7851f54c0dee86b2bf55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/080db3af81b29ed10144a1c2e2a4fb8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e2512ffe4864827d4aeaa1394ba01eb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4560fa4ad459b58b723c74bd24e51ebf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9afac7c616bbb14e1ed428a3c507c7dc.png)
(2)求平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74bca84ad86c648d3bb20c8909c8da3f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab3e0dba5705e1d749cfb21ebbb2ed93.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
【推荐3】如图,圆台
的轴截面为等腰梯形
为下底面圆周上异于
的点.
(1)在平面
内,过
作一条直线与平面
平行,并说明理由;
(2)若四棱锥
的体积为
,求平面
与平面
夹角的余弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e65ac334119ccd6204402a7aba29a55.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c2ce374287359fd2676dcada2ffb382d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/098a3e7d1f1890863b7483a98b618119.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/7/25/3c55e150-89de-4b7f-9f18-4466a9f32595.png?resizew=173)
(1)在平面
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8f664c0db517bec6886ff0b6100fd474.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b1241216f3c1cb5e73043dd1037f556d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edc9ffc43a56921fe79f8602636b8b0f.png)
(2)若四棱锥
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/29a0c82028e1259f300facd32775a15e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38387ba1cadfd3dfc4dea4ca9f613cea.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/edc9ffc43a56921fe79f8602636b8b0f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/23e2c643dd6501b20c46c5c6527a2634.png)
您最近一年使用:0次