先化简,再求值
)的值,其中x=8sin30°+2cos45°.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/95eddc1426b2d07e2a1917ffab950cd8.png)
更新时间:2019-11-08 19:35:02
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相似题推荐
解答题-计算题
|
适中
(0.65)
【推荐1】先化简,再求值:(1+
)÷(x-
),其中x=
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8ef6dd54ec8d25ba7043c06f36fd1a51.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8788b6c813805d5a3504e819f74fffd6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
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解答题-计算题
|
适中
(0.65)
【推荐2】阅读理解:
已知a=
,求2a2-8a+1的值.
∵a=
=
,
∴a-2=
.
∴(a-2)2=3,即a2-4a+4=3.
∴a2-4a=-1.
∴2a2-8a+1=2(a2-4a)+1=2×(-1)+1=-1.
请根据以上解答过程,解决如下问题:
(1)计算:
____.
(2)计算:
;
(3)若a=
,求2a2+12a-8的值.
已知a=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d46d903100e4258ef742d56efdeeb156.png)
∵a=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d46d903100e4258ef742d56efdeeb156.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/789c70bd207ffa17d0c1288722a8a082.png)
∴a-2=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
∴(a-2)2=3,即a2-4a+4=3.
∴a2-4a=-1.
∴2a2-8a+1=2(a2-4a)+1=2×(-1)+1=-1.
请根据以上解答过程,解决如下问题:
(1)计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ddae19bb3afde7d149a7752f9e4c4ffc.png)
(2)计算:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/474a6f80459e75a2bebb0ad7526dbe52.png)
(3)若a=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d946f2b581d098571e360f652feb1fed.png)
您最近一年使用:0次
解答题-计算题
|
适中
(0.65)
【推荐1】化简求值:当
,
时,
(1)求
的值;
(2)求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/12bbef9e71d48868c688fbc362de13d2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9d97c6fa48d35109e2d1f4c280513ba0.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1d0f21d91ba8c4d7a9ea415af0ee2f9.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3a9ed32a7764a8d7908c0c0439be0e4d.png)
您最近一年使用:0次
解答题-计算题
|
适中
(0.65)
【推荐2】计算:
(1)(2
﹣3
)÷
;
(2)(
)×
;
(3)已知:x=
+2,y=
﹣2.求x2+xy+y2的值.
(1)(2
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f46f33f578fbb88a7525ef32e7126856.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38fda303240e35a04641e7e602dcc414.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a7ffe8515ff6183c1c7775dc6f94bdb8.png)
(2)(
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/caa9d4f4487b3b9e1cbfd4e16882c32d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/573491a321b053cb696038d332fc610b.png)
(3)已知:x=
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2967337e3fcb228dded64ab0c41a17e0.png)
您最近一年使用:0次