已知函数
.(
是自然对数的底数)
(1)求
的单调递减区间;
(2)记
,若
,试讨论
在
上的零点个数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3309b6e2a4ed81c120db4555d32a09c4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/041a7c8fc017f596542c5e6ec7d1c40b.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
(2)记
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/00210f79b04a8f6bc1922433d00bc89a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/37c84b49231d0344d0813a7bbd2acdaa.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4669810732b633b60dbeaf0bf57204f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/71163f419555f2ed76075c8ff659fbfc.png)
2024·四川成都·一模 查看更多[4]
更新时间:2023-12-28 13:11:06
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名校
【推荐1】武汉出现的新型冠状病毒是一种可以通过飞沫传播的变异病毒,某药物研究所为筛查该新型冠状病毒,需要检验血液是否为阳性,现有
份血液样本,每份样本取到的可能性均等,有以下两种检验方式:①逐份检验,则需要检验n次;②混合检验,将其中
份血液样本分别取样混合在一起检验.若检验结果为阴性,这k份血液全为阴性,因此这k份血液样本检验一次就够了,如果检验结果为阳性,为了明确这k份血液究竟哪几份为阳性,就要对这k份血液再逐份检验,此时这k份血液的检验次数总共为
次.假设在接受检验的血液样本中,每份样本的检验结果是阴性还是阳性都是独立的,且每份样本是阳性结果的概率为
.
(1)假设有5份血液样本,其中只有2份为阳性,若采取逐份检验方式,求恰好经过2次检验就能把阳性样本全部检验出来的概率;
(2)现取其中
份血液样本,记采用逐份检验方式,样本需要检验的次数为
,采用混合检验方式,样本需要检验的总次数为
.
(i)试运用概率统计知识,若
,试求P关于k的函数关系式
;
(ii)若
,采用混合检验方式可以使得这k份血液样本需要检验的总次数的期望值比逐份检验的总次数期望值更少,求k的最大值.
参考数据:
,
,
,
,
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/223ed9652852ca4d996fd1f20808df9a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a6ee7658476cc293b4cade8fc72cb16d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b00f4eb7f1bd2ccefbabf0c1dfa8f69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/44fed1be8b7e50f18cb90077d9fce8e4.png)
(1)假设有5份血液样本,其中只有2份为阳性,若采取逐份检验方式,求恰好经过2次检验就能把阳性样本全部检验出来的概率;
(2)现取其中
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b2a3d9f101e3b520b93b2052b61e202b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d388f32e318b0c7f2d9d10a5c6525b15.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/90f1ce5bbcc57f96d99d2c4f27cc2e42.png)
(i)试运用概率统计知识,若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6bd314aee9f06722598766b752fa1e73.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2816d5333484a85383df0cd62c7225f0.png)
(ii)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/136138fa62de53021656ab726fad8ef3.png)
参考数据:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b0591d9f78b4f4f78c5bd6baaa602ae0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/289ad328bffb5f497153dc0e59939257.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4086cd22f9543d857140a3a8e0a7fec9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3616e69114889d5d02099b6598a57136.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/401bda9057eb0da43fba681130b558f3.png)
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解题方法
【推荐2】已知函数
.
(1)求函数
的单调区间;
(2)实数
,
满足
,求
的最大值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7ce68391c27cdec30cef2fddcc30f366.png)
(1)求函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
(2)实数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c814128ea2139e33db94ea590e7c2223.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aec19b68e3add9d5bfcc6269a1855b87.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/538e0060ac739f7227a6869de080c9fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0254d8832cb08052fac056b7aad207b5.png)
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【推荐1】已知函数
.
(1)讨论函数
的零点个数;
(2)证明:当
,
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/030de51667a1159750331f002c329247.png)
(1)讨论函数
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
(2)证明:当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/930bc56406e69b785b37a83d48e36724.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d685c9c2f6685e9c49a71bdd17d6714.png)
您最近一年使用:0次
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(0.4)
名校
【推荐2】已知函数
,
(
为常数,且
).
(1)若当
时,函数
与
的图象有且只要一个交点,试确定自然数
的值,使得
(参考数值
,
,
,
);
(2)当
时,证明:
(其中
为自然对数的底数).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/240823ab0de96f9b41d10b08cad290d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d8dc4436bc4b55be30dc1453facf0dfa.png)
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(1)若当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a6330540758a21f46fc7a6d1e6328d8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4669810732b633b60dbeaf0bf57204f6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6a24198bd04c29321ae5dc5a28fe421.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/98672f2785636c0fa57c4ef56576b430.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1597277c8cb70bc9aaed8a21fc0cbea6.png)
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7c0309456de2cd6420ece4fbc5eeddb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3da3f388d4c6a907e265a5f1902cb717.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/752455799e49f846e2601304fec5d3b8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c9da7290ae4b1f43c81cf08722edab69.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/041a7c8fc017f596542c5e6ec7d1c40b.png)
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【推荐3】已知函数
.
(1)求曲线
在点
处的切线方程;
(2)当
时,求函数
(
为
的导函数)在
上的零点个数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7851b8221a1799d2062c4687987429a8.png)
(1)求曲线
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/942c2141d01bde6b48210c56a17fc75e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c9f8845aa2b51c460f2d798c9f62fa3.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8a2f4630b66f80a5f2b7f186e49b321e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b125c204b01d4eda72a6ef6e73153da1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/724340d69477c0ec2418c392b22b1cab.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/09f86f37ec8e15846bd731ab4fcdbacd.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d3ff8dca35b759d3051b62badd7d76bc.png)
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