1 . 已知等边
和等腰
,
,
.
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/22/3b21bf14-7e13-406f-bec0-24a361ad8888.png?resizew=463)
(1)如图①,点D在BC上,点E在AB上,P是BE的中点,连接AD,PD,求证:
;
(2)如图②,点D在
内部,点E在
外部,P是BE的中点,连接AD、PD,则(1)中的结论是否仍然成立?若成立,请给出证明;若不成立,请说明理由;
(3)如图③,若点D在
内部,点E和点B重合,点P在BC下方,且
为定值,当PD最大时,请直接写出
的度数.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d631f45bc652539853f236952afa5bbf.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/df34369163e511f14028168cb0b21186.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f4a098e98e74db40a5aa08eba09a46f.png)
![](https://img.xkw.com/dksih/QBM/editorImg/2022/12/22/3b21bf14-7e13-406f-bec0-24a361ad8888.png?resizew=463)
(1)如图①,点D在BC上,点E在AB上,P是BE的中点,连接AD,PD,求证:
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/275a94c3e3aa85acb13634aa0b03aae2.png)
(2)如图②,点D在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
(3)如图③,若点D在
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/15c0dbe3c080c4c4636c64803e5c1f76.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f4d1d99eab930cef884e01b97d4d56f1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ef0433f8116768b42642a7f7e5977ce6.png)
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2 . 对任意一个三位自然数n,若各个数位上的数字均不为0,则称该自然数为“无零数”.将这个三位“无零数”的各数位上的数字两两组合,形成六个新的两位数,我们将这六个两位数的和,叫做该三位“无零数”的“二位总和”,将所得的“二位总和”除以44,得到的结果记为
.例如“352”是一个三位“无零数”,六个新数为35,32,53,52,23,25,则
.
(1)
________,证明:任意一个满足十位数字等于百位数字与个位数字之和的
的三位“无零数”,它的“二位总和”定能被33整除;
(2)若一个“无零数”
(其中
,
,且a,b为整数)的十位数字为8,且满足十位数字等于百位数字与个位数字之和,求
.
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/38fcec7af3520884b173b29bda6c657a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/11ddc96b610d61898618ffe3589c1582.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/2a09c6c93458b3441a17ada2deb8034e.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f89eef3148f2d4d09379767b4af69132.png)
(2)若一个“无零数”
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/d66b2f408adab263143c65369241027a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a6fe0a044511f71c14c4a710f358581.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/3c9683c0a95aaeda96c5793b0f695d54.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/c3f81f2a0196b06fc56a7e8a6463d179.png)
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