已知
、
是方程
的两实数根.
(1)求
的值.
(2)求
的值.
![](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/95abf9806a586b4c7ab5c70fb1b061ce.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7d19f804dd3de9d40b1d43c3bddd4136.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/30e1ec316ce8efce15053b24806f148f.png)
更新时间:2021-12-09 16:48:02
|
【知识点】 一元二次方程的根与系数的关系解读
相似题推荐
解答题-证明题
|
适中
(0.65)
【推荐1】问题:已知实数a、b、c满足
,且
,求证:
.
小明在思考时,感觉无从下手,就去请教学霸小刚,小刚审题后思考了片刻,对小明说:我们可以构造一个一元二次方程,利用一元二次方程根与系数的关系及整体代入即可解答,并写下了部分解题过程供小明参考:
令
,则
,原等式可变形为关于x的一元二次方程:
.
可以发现:
.
从而可知构造的方程两个根分别是1和![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d6604a5595dfe260992023adf927134.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/882a6e8f86e28c2382ab50e2c8ab0c0c.png)
利用根与系数的关系得:
_____;
_____;…
请你根据小刚的思路完整地解答本题.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2958030ec9d7543dda1f529593a915e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/043f0ecf173191accabf73579984bb4c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/68094dc6cced4b33d0de84a5b380e1a6.png)
小明在思考时,感觉无从下手,就去请教学霸小刚,小刚审题后思考了片刻,对小明说:我们可以构造一个一元二次方程,利用一元二次方程根与系数的关系及整体代入即可解答,并写下了部分解题过程供小明参考:
令
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9e9b1ed6256002fe64f47112e696e8f8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e23ef6ff5ec28bd2bb1be8051e86e5f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6170940baaaaf01f689be4880b687a4.png)
可以发现:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cf33cf54a8e068129ca6dce93dc3f159.png)
从而可知构造的方程两个根分别是1和
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1d6604a5595dfe260992023adf927134.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/882a6e8f86e28c2382ab50e2c8ab0c0c.png)
利用根与系数的关系得:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/724697dec4e5b7ded274ac908e785d4b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96cbe4784fb9bf80bbb631b07d1ab430.png)
请你根据小刚的思路完整地解答本题.
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解答题-计算题
|
适中
(0.65)
【推荐2】阅读下列材料,并解决问题.
(1)已知方程
的两根分别为
,计算:
_____,
_____.
(2)已知方程
的两根分别为
,
,计算:
_____,
_____.
(3)已知关于
的方程
有两根分别记作
,且
,
,请通过计算
及
,探究出它们与
的关系.
(1)已知方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4cef1c6de51e6d2f0aae7518a632fe0f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e7085e1aa0d291cb36921ac8329c0787.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97dad16e4910ec15add074c4077b0e86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/822fad5b69f29ce514e977e0b3e0ecc1.png)
(2)已知方程
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3898b62d3fbcb61afb6bc1e9b910f564.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c4223bd6ee8f82d59d244371fbcddc5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ac12f90931435d60f4b6879ab26f7a0b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/97dad16e4910ec15add074c4077b0e86.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/822fad5b69f29ce514e977e0b3e0ecc1.png)
(3)已知关于
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/783a7b78d895784b4af75b962bd40f07.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ce7ae90d808f05e86ea063238e4b2f9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4179dc297ed1d098e07c70597f6a23ed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/616c919b310777091ead6b33aab02a9e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/450398974b1561ca801e102e16df6789.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28b6ab702f8e93cc1e680a7d7af06786.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0cd5371a6f0f82c65dd22f75f8b807c1.png)
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