已知集合
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f2e04d6dc52279058b64d1ade529d74f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2dbda9c2670defdec517a691a4a1e920.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b4b9b470218359a4a47be9244980489e.png)
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更新时间:2023-02-03 11:28:52
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解题方法
【推荐1】集合
,
,则
( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d40959494d0d33e3f6ec9fa6c8d9c4d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf152f5223d6b7370858c29c89184c8d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1336d38741aab2255a35c26612bbd7cc.png)
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【推荐1】20世纪30年代,里克特制定了一种表明地震能量大小的尺度,就是使用地震仪衡量地震能量的等级,地震能量越大,测震仪记录的地震曲线的振幅就越大,这就是我们常说的里氏震级M,其计算公式为
,其中A是被测地震的最大振幅,
是标准地震的振幅,2008年5月12日,我国四川汶川发生了地震,速报震级为里氏7.8级,修订后的震级为里氏8.0级,则修订后的震级与速报震级的最大振幅之比为( )
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/964ba375cf71028efc5125ad478abbb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7356ec98b600ece41f3a6b4bc26a7d59.png)
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【推荐2】某种用保温材料制成的管道在单位长度上的热损失
单位:
满足
,其中
分别为管道的内外半径(单位:
),
分别为管道内外表面的温度(单位:
),
为保温材料的导热系数(单位:
),某工厂准备用这种管道传输
的高温蒸汽,根据安全操作规定,管道外表面温度应控制为
,已知管道内半径为
,当管道壁的厚度为
时,
,则当管道壁的厚度为
时,
约为( )
参考数据:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c08050c68d75ace3df7742b4c8fe672f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab37410fab0feb61357bb57d4c205fa8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03de4fce77f51595c922400f5eecd069.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ff8543261a8e351eb95cdfebb001a3b4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/21f3bf70722b22983c120d008d097602.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6ae8e9f49a0c2862c0672ff6e12454be.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aa088a4729226b696c536845791d4c02.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df64046e91b047037f19e4032e3b6de3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f83c986fba81567b92b804a0a10c4939.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2b8034dc11cd61db2883c1449896610a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dce3bddc9396deaf856eca6ac14594b3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a0401a0e51b089310207773f1c83be76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4db74a039efbf820b2e184f468633686.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6e803d6015d29ef12098042e1beb2488.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c077e21affbe7f9f8bb6d1f57b7e6c59.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28da263b0995b8d36e0b313259e38f98.png)
参考数据:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3d0cdb790723fddea50b6bef0626f47a.png)
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