如图,在平面四边形ABCD中,CD=1,BC=2,∠C=120°
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/11/7151be84-af66-4b8d-9a4b-7a93aab8d366.png?resizew=168)
(1)求cos∠CBD的值;
(2)若AD=4,cos∠ABC
,求∠A的大小.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/11/7151be84-af66-4b8d-9a4b-7a93aab8d366.png?resizew=168)
(1)求cos∠CBD的值;
(2)若AD=4,cos∠ABC
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22f4550a7fa019e9b22dfdf3164e816b.png)
更新时间:2019-10-11 19:57:43
|
相似题推荐
解答题-问答题
|
适中
(0.65)
解题方法
【推荐1】在
中,![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047f6adc83623efff82b022782a250ba.png)
(1)求
的值; (2)求
的值; (3)求
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/047f6adc83623efff82b022782a250ba.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/436de5fa22406630d62c9878bf414dd2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.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】若函数
(
),非零向量
,我们称
为函数
的“相伴向量”,
为向量
的“相伴函数”.
(1)已知函数
,求
的“相伴向量”;
(2)记向量
的“相伴函数”为
,将
图象上所有点的横坐标伸长到原来的
倍(纵坐标不变),再将所得的图象上的所有点向左平移
个单位长度,得到函数
,若
,
,求
的值;
(3)对于函数
,是否存在“相伴向量”?若存在,求出
的“相伴向量”;若不存在,请说明理由.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/65c6f29b2b1955715616003d51d8b77f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/773ca22fc12ade9e60dbc749ba5cfa73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e02a2530966362c93c56617f448f449c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/294f5ba74cdf695fc9a8a8e52f421328.png)
(1)已知函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/53bf638cbaa2321e25f2e5a2bb48ea2c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
(2)记向量
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4c917a01eab9c7fbabef4382d32a0257.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be1ce3f01e2b6364f9a9fdaf197d5e29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/be1ce3f01e2b6364f9a9fdaf197d5e29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/61128ab996360a038e6e64d82fcba004.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c0211da37e92f915e781691296578ba0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0eb7df298a9364b36e079a61caec815c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a1bea28b97aeeb961b2522670dbc4b0a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/046387911745f43ff3b6804ea58eb26a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0b4179e1ab8705cf19ea7aaf48888843.png)
(3)对于函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bab529b3f6a52dbe10551dfc8ec57d5a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8b2775ffdf695af2d263f0ea93ac5904.png)
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】从条件①
,②
中任选一个,补充到下面的问题中并作答.问题:在
中,角
,
,
的对边分别为
,
,
,且
,
,求边
.注:如果选择多个条件分别解答,按第一个解答计分.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0adf2271434af2d2b9433231c1c80637.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dcb5bac75f36bb1dc5c8190d4dbe681d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab839d8569171afab5ed55c22013aa72.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2f44c181a2f6ae22d5d52b374768dc57.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
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2】
的内角
的对边分别为
,已知
.
(1)求
的值;
(2)若
是
上一点,
,求
的面积.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/24e0c10fb103930eabd5fa18e8f9bb06.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/76f0649064a085fb74c997fb507a9b6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/74b91521d05e0133dd3fee59de2390dd.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c32e2f2d7147cf1699fbfdef9cf4af74.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0dc5c9827dfd0be5a9c85962d6ccbfb1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c828839ec7daffe75d61c24298afe7a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab2a2834d80ff574e79eae8ca8d4e94f.png)
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】在
中,角
,
,
所对的边分别为
,
,
.已知
,且
.
(1)求
的大小;
(2)若
的面积为
,求
的周长.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f7fa79a550591eb9e1bd07bced3a08fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c7a722d6bc7ca3f4fe38e0f3b0d1c7a.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a4b8503f4706b8321e4e79a87eadea84.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
【推荐2】如图,在四棱锥
中,底面
为等腰梯形,
,
,
平面
,
,点
为线段
中点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/1/a9f935db-30a7-4ee1-b8c9-ef0bdf23f907.png?resizew=156)
(1)求证:
平面
;
(2)求直线
与平面
所成角的正弦值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/faeb97acf19bd3b2c6c77c2814df4d2f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f571396be1aa4a8914a66f7d7abd6381.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c6e0b64d25ddd18454f88e40c45d7d8f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/10c83f8945042b9c8fb2fbdac9308d62.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/411b38a18046fea8e9fab1f9f9b80a5f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/39c049bbf873a6af116712840484b98f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0ed1ec316bc54c37c4286c208f55667.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/defa5b53043ae802bb1af7d14374406d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/8/1/a9f935db-30a7-4ee1-b8c9-ef0bdf23f907.png?resizew=156)
(1)求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5a5928c98b341b16d4b5a5b931d2929d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bc9c9cfa597b444b5c9dbae7a825a695.png)
(2)求直线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/735056c174e8dd7906257a2a50a962a7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5000fea066102e62cf2128ccbbd2b3e3.png)
您最近一年使用:0次