名校
1 . 在近期学校组织的论文展示大赛中,同学们发现数学在音乐欣赏中起着重要的作用
纯音的数学模型是三角函数
如音叉发出的纯音振动可表示为
,其中
表示时间,
表示纯音振动时音叉的位移
我们听到的每个音是由纯音合成的,若某合音的数学模型为函数
,且声音的质感与
的参数有关,比如:音调与声波的振动频率有关,频率低的声音低沉,频率高的声音尖利.
(1)当
时,函数
的对称中心坐标为______ ;
(2)当
时,合音
的音调比纯音![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7a72ab550b89f838b0f71a24c20f4bb.png)
______ (填写“高”或“低”).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c90282d4a37c9a20620d4bbb0c263cae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c90282d4a37c9a20620d4bbb0c263cae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/42f0670a61f0274e80b47844cea59ac1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d053b14c8588eee2acbbe44fc37a6886.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c90282d4a37c9a20620d4bbb0c263cae.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/8fe5c8a68ce20e3b6551d9fb67ea85fe.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/51c530f4b7491b95acb8ce3eef9aa09d.png)
(1)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c87b351f16728b0023fd63678f8103c7.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
(2)当
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d0b87383da5b68e452263e205594f334.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c7a72ab550b89f838b0f71a24c20f4bb.png)
您最近一年使用:0次
2 . 设平面中所有向量组成集合
,
为
中的一个单位向量,定义
.则下列结论中正确的有___________ (只需填写序号).
①若
、
,则
;
②若
,
,则
;
③若
,
,
,则
有唯一解
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3dc64abe49847ade9b78678ba1f8e0e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c5db41a1f31d6baee7c69990811edb9f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/01ab4307c9909f1eac26b6a235dcce5a.png)
①若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4f7a1df960feef63dec4790d63f52279.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2d6d538e2f7f05f764e279bd7d8a4a9b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e8509e22fb1981a8cadcfebec0423c3e.png)
②若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/84351bb40ab6d410389d9ffe89712ce5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7de20046dd30dd69b495bd98542694d1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/05807c9028ec05f2619107ebb654ead2.png)
③若
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b143cc353e3d07e0706f0a6e248289c.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/269b70a69778d23918c580fed8653ee3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cd4b296e3fa718e527e40cf53d175610.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3dc64abe49847ade9b78678ba1f8e0e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/41bc1b7849fd111596d3425dbb5f4d55.png)
您最近一年使用:0次
2022-05-07更新
|
219次组卷
|
2卷引用:北京市第十九中学2021—2022学年高一下学期期中数学试题
名校
解题方法
3 . 声音是由物体振动而产生的声波通过介质(空气、固体或液体)传播并能被人的听觉器官所感知的波动现象.在现实生活中经常需要把两个不同的声波进行合成,这种技术被广泛运用在乐器的调音和耳机的主动降噪技术方面.
(1)若甲声波的数学模型为
,乙声波的数学模型为
,甲、乙声波合成后的数学模型为
.要使
恒成立,则
的最小值为____________ ;
(2)技术人员获取某种声波,其数学模型记为
,其部分图像如图所示,对该声波进行逆向分析,发现它是由S1,S2两种不同的声波合成得到的,S1,S2的数学模型分别记为
和
,满足
.已知S1,S2两种声波的数学模型源自于下列四个函数中的两个.
![](https://img.xkw.com/dksih/QBM/2021/4/29/2710414906130432/2785822478147584/STEM/0fc4af214bc64755ae531956a531ed4d.png?resizew=313)
①
; ②![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03b3f17664e57122bba6d8d8dd75c914.png)
③
;④![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c4517380712240e48c4569863e6fdf.png)
则S1,S2两种声波的数学模型分别是_________ .(填写序号)
(1)若甲声波的数学模型为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ecf0499eb96d6af7cdfea79540ae2860.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/45dbec5a3ac2e57eeb24e82af5c4667f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd67b594f222d83c217262f94089ddc9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/9c419949314258c61e4436e16477fa42.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6581916f5a65edfea257c804efee007e.png)
(2)技术人员获取某种声波,其数学模型记为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/26e91406484c332ac8fc96a54c7e187b.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2709ca478fb15ea08e8aa55328eae8e6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a82a1224e47f31ecdfffd328d5a3ab6d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/585abcc61e51a9e73513b95155a8da45.png)
![](https://img.xkw.com/dksih/QBM/2021/4/29/2710414906130432/2785822478147584/STEM/0fc4af214bc64755ae531956a531ed4d.png?resizew=313)
①
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c179fc593b49cf3a5d57b691b5b2ee45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/03b3f17664e57122bba6d8d8dd75c914.png)
③
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b3bd853f3df2d9dbc4b846d296d5297d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c4517380712240e48c4569863e6fdf.png)
则S1,S2两种声波的数学模型分别是
您最近一年使用:0次
2021-08-14更新
|
836次组卷
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6卷引用:北京市海淀区2020-2021学年高一下学期期中数学试题