20-21高一·全国·课后作业
解题方法
1 . 作用于同一点的三个力
,
,
平衡,且
,
的夹角为
,
,
的夹角为
,
,
的夹角为
.求证:
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5076289823db419f94e9c0c8f4aafd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3fb78c5f885034612c0e030b920143d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1282962a17a48a18edf733204054d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5076289823db419f94e9c0c8f4aafd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3fb78c5f885034612c0e030b920143d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3e8d4017e1a37acb0c8e00508be472b2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3fb78c5f885034612c0e030b920143d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1282962a17a48a18edf733204054d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/25f64fa38725c136504f723019a18dc5.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1282962a17a48a18edf733204054d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5076289823db419f94e9c0c8f4aafd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e93fa313adc4ac7608ba9449fd755212.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3efc05223fdcb10bb8082911ce472301.png)
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20-21高一·全国·课后作业
2 . 曲柄连杆机构的示意图如图所示.当曲柄
在水平位置
时,连杆端点
在
的位置.当
自
按顺时针方向旋转角
时,
和
之间的距离是
.已知
,
,根据下列条件,求
的值(精确到
):
;
(2)
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a299d2b999568e80be8005565ba209a4.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef4113c492885ba7c47fe42ac792578f.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b90e0f35eda1a729fed485f83da5ea9d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e170f206fdbbd834aad7580c727e2cc6.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/acc290b44635265137fdf13146b6a6d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d19f6c71e82001bb106b6f1389046b79.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ad2b22270370a3e26f9edd544bb95793.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e4a6e1f57fb799a3fd252e57690649e2.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/263a592442ba4c97ad21d02216e720a8.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/453802422f80928bda9e11200b3c636d.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d44c15e23e4d1c752383d1ae5f3189f1.png)
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3 . 如图,用两根绳子牵引重为
的物体,两根绳子的拉力分别为
,
,此时平衡.如果
,
与
的夹角
.
的大小(精确到1N);
(2)求
与
的夹角
的值(精确到0.1°).
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/cb0a7565dbb8e665bb691d1de0c73675.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3fb78c5f885034612c0e030b920143d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1282962a17a48a18edf733204054d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b6773de8f14f06da06bf9c6f22738c6e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a3fb78c5f885034612c0e030b920143d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1282962a17a48a18edf733204054d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e3bea7383acbd1da6d0d5f10ef1b2aed.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1282962a17a48a18edf733204054d67.png)
(2)求
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d1282962a17a48a18edf733204054d67.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f5076289823db419f94e9c0c8f4aafd9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5b5858ee1ce52b251816757257a11c29.png)
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20-21高一·全国·课后作业
4 . 在
中,斜边c等于
外接圆的直径2R,故有
,这一关系对任意三角形也成立吗(如图)?探索并证明你的结论.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dd967903ed5a6f640a5b801ec8be0070.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c30b12f8bf54428846cf378ffd5a23b7.png)
![](https://img.xkw.com/dksih/QBM/2021/11/11/2849051998388224/2849773829832704/STEM/9fe85621-a425-48b5-b514-51d363e38aa8.png?resizew=355)
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20-21高二·全国·课后作业
5 . 求下列等比数列的第4项和第5项.
(1)
;
(2)
;
(3)11,3.3,0.99,…;
(4)
.
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/752a213648644dbc4ac9de9cf311489c.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/969c3a49dace76652e652575df6631e2.png)
(3)11,3.3,0.99,…;
(4)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e6f12b33f94ab9d96bff92b610429b1a.png)
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20-21高二·全国·课后作业
6 . 分别写出一个满足下列条件的数列
的通项公式.
(1)从第2项起,每一项都比它的前一项大2;
(2)
是无穷递减数列,且从第2项起,每一项都是它的前一项的3倍.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)从第2项起,每一项都比它的前一项大2;
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
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20-21高二·全国·课后作业
7 . 写出以下各数列
的一个通项公式,并根据你写的通项公式求出各数列的第10项.
(1)
;
(2)
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/83cf38189d5cbf627d2b82ac0eb76006.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/e76f2d1e314ee9d17826436a38cbec14.png)
(2)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7abfa05b0dd1baf6039288cec6cacb9a.png)
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20-21高二·全国·课后作业
8 . 中国人民银行2015年10月24日公布的“人民币现行利率表”显示,金融机构人民币贷款一至五年(含五年)的基准利率为4.75%.若某人年初时从某银行贷款了100000元,贷款期为5年,贷款利率就是基准利率,银行每年年底结算一次利息.求到第5年年底时,该人欠银行的钱数(精确到0.01).
您最近一年使用:0次
20-21高二·全国·课后作业
解题方法
9 . 假设某工厂生产某种产品,第一年产量为a,以后每年该产品产量的增长率是
,用
表示第n年该产品的产量,用
表示从开始到第n年该工厂生产这种产品的总量,分别求出
与
的表达式.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/fcd94bc1b9f9ae8b134df382a16cbeec.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/96abfe2da27a63e6affb19a0c80236d9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/08eb71ecf8d733b6932f4680874dbbf3.png)
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20-21高二·全国·课后作业
10 . 已知安装在一个公共轴上的5个皮带轮的直径成等差数列,其中最大的与最小的皮带轮的直径分别为
与
,求中间3个皮带轮的直径.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/66e66d5ff831e837398b871441f9479e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c077e21affbe7f9f8bb6d1f57b7e6c59.png)
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