已知
.
(1)求
的值;
(2)求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2ded2f59e5a38b437cf6e72a361d1aab.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6f90c4754e6b6fc862d72943fb35569.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6cc9750c313ee972124cb62c4a6fb7ea.png)
更新时间:2023-03-28 21:03:47
|
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解答题-计算题
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适中
(0.65)
解题方法
【推荐1】已知
,且函数
.
(1)化简
;
(2)若
,求
和
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a17491898e262bf44270327387e38ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28e242567e200525d123dbd86658a1bb.png)
(1)化简
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/794f2c6bd63355105d179d11306a9cae.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd2a4f13258169021040da6d056c9e40.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/617e59c1afb7dc761f5b373bc820ecff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9db589bebb2f413b51ab7d684f7eb990.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】已知函数
.
(1)若
,求
的值域;
(2)设
,
,且
,
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6eedcd28e148c99a6206eb763af3ae75.png)
(1)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3eaadcab89562a4e8c7036809148a82f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
(2)设
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5f72e28ac98490434f3e751182423fb7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/291fb4be5b46a35f45912e7d32cb4c5c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1a17491898e262bf44270327387e38ff.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1ac254947eccb2781a6a9ff2adf0504a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9381b769d58b82926d9daec0fee14345.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】(1)已知
,求
的值.
(2)求函数定义域:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/600f5e3d17ba310a372c28872f898ee1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e2ae8f4041d64ef1c688e0c4a7b366b0.png)
(2)求函数定义域:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b88cbe78f510a0aed628c29c9ff837a6.png)
您最近一年使用:0次
解答题-问答题
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适中
(0.65)
解题方法
【推荐1】已知
,
,
,
.
(1)求
的值;
(2)求
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![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fd640674fdfe6aee31b6234232a15dd8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/af506f20422b16215c48de6abe580d29.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9918d857fc66ed2e2de97c61de7a491c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/04cf67d13e29ec0d0d3d45e7d6ebd381.png)
(1)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9146fc0a63e5c14a8fa46573e60c07ba.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6abc69c57972a4efb8301e3308ea9ca6.png)
您最近一年使用:0次
解答题-问答题
|
适中
(0.65)
名校
解题方法
【推荐2】在
中,角
,
,
的对边分别为
,
,
,已知
,
,
,
为三个相邻的自然数,且
.
(1)证明:
;
(2)若
,
,求
的值.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ce613eaa5df46a50174085ef5d1087fb.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/0a6936d370d6a238a608ca56f87198de.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2c94bb12cee76221e13f9ef955b0aab1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/071a7e733d466949ac935b4b8ee8d183.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7b9446d7b31f0d6e044cf99deeb20aa.png)
(1)证明:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ebd23aaafa6a08df860bad3736b2064e.png)
(2)若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef001eeef468ca21ac0cbb23fd135657.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9923f4f4d4e0dbf1e11e4e708e84de2b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/aefd06c239145a2b6ae87a955aa51414.png)
您最近一年使用:0次
解答题-证明题
|
适中
(0.65)
名校
解题方法
【推荐1】由倍角公式cos2x=2cos2x-1,可知cos2x可以表示为cosx的二次多项式,对于cos3x,我们有cos3x=cos(2x+x)
=cos2xcosx-sin2xsinx
=(2cos2x-1)cosx-2(sinxcosx)sinx
=2cos3x-cosx-2(1-cos2x)cosx
=4cos3x-3cosx
可见cos3x可以表示为cosx的三次多项式.一般地,存在一个n次多项式Pn(t),使得cosnx=Pn(cosx),这些多项式Pn(t)称为切比雪夫多项式.
(1)求证:sin3x=3sinx-4sin3x;
(2)请求出P4(t),即用一个cosx的四次多项式来表示cos4x;
(3)利用结论cos3x=4cos3x-3cosx,求出sin18°的值.
=cos2xcosx-sin2xsinx
=(2cos2x-1)cosx-2(sinxcosx)sinx
=2cos3x-cosx-2(1-cos2x)cosx
=4cos3x-3cosx
可见cos3x可以表示为cosx的三次多项式.一般地,存在一个n次多项式Pn(t),使得cosnx=Pn(cosx),这些多项式Pn(t)称为切比雪夫多项式.
(1)求证:sin3x=3sinx-4sin3x;
(2)请求出P4(t),即用一个cosx的四次多项式来表示cos4x;
(3)利用结论cos3x=4cos3x-3cosx,求出sin18°的值.
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