名校
解题方法
1 . 已知
且
,
,选项中的命题都正确的是( ).
(1)不等式
恒成立;
(2)设
,
,
,
,
,如果四边形
的面积为s,那么存在
使
成立;
(3)对任意
时,不等式
恒成立;
(4)对任意
时,不等式
恒成立.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af1184f3f4147174e6b465db671b3e15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3be362dec96173f246ff747264007817.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51c98c0ec4c99989333faa478a946985.png)
(1)不等式
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e45e8aa45aeebc0d08464a136347e60.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26d8dafc71b106f39f4e15442220897b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d1784ef4e8a2b1b49256b61f2b306b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b16c61b3d678794a5873964635724da1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fa6b09f39af8d61f60a430cbcadc6027.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38463103bd5a2c973103f1d2b186b668.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b9b7b7793d29d66dfdd89e7a6564a35c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d54ed8c334b341c9f5016272d7774145.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b952a0885768207cc0f026a843ff3008.png)
(3)对任意
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6096acdd2d0ce16e1e45397ec5e365d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b21956468c14cd2b8142d63d8ce3a7a8.png)
(4)对任意
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6096acdd2d0ce16e1e45397ec5e365d4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/75d5fd775c4fbb429f3dc736cdf3eeec.png)
A.(1)(2)(3) | B.(1)(2)(4) | C.(1)(3)(4) | D.(2)(3)(4) |
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名校
解题方法
2 . 如图,在平面直角坐标系中.锐角
、
的终边分别与单位圆交于
、
两点.
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/158c94e0-7054-4c1d-a8c3-7242a7e8bfbe.png?resizew=164)
(1)如果
,
点的横坐标为
,求
;
(2)若
,将角
的终边按逆时针方向旋转
后与单位圆交于点
,求角
的大小及四边形
的周长;
(3)若角
的终边与单位圆交于
点,设角
、
、
的正弦线分别为
、
、
,试探索线段
、
、
能否构成一个三角形?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2023/2/2/158c94e0-7054-4c1d-a8c3-7242a7e8bfbe.png?resizew=164)
(1)如果
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/541855d25afe0cfb489eeaa157daf59d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d63d1200ef5de2c40f2022af10a87b74.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/22d521f8d021b20757d7a68107fcef1d.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bbc790cfaa59a808c25a7edb95dc29fc.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c550484116296268d293158d9ff9e630.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/db16c2860a8881cdfcaec890f2948304.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c24095e409b025db711f14be783a406c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/607543bb9f55b8a141ed2d6cf0e1a20b.png)
(3)若角
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8dc4c63a548b91061528aa11058de75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8455657dde27aabe6adb7b188e031c11.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b8dc4c63a548b91061528aa11058de75.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b66a5b7813e902306477f91f9f4084cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/279563c3c055777ce1aa369a2ef54aed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b66a5b7813e902306477f91f9f4084cd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/279563c3c055777ce1aa369a2ef54aed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e0629ce42392a7fe9be21d25c39c3e64.png)
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