1 . 某地拟建一座长为
米的大桥
,假设桥墩等距离分布,经设计部门测算,两端桥墩
、
造价总共为
万元,当相邻两个桥墩的距离为
米时(其中
),中间每个桥墩的平均造价为
万元,桥面每1米长的平均造价为
万元.
![](https://img.xkw.com/dksih/QBM/2015/7/30/1572198128050176/1572198134079488/STEM/751580b6358f4eff81f05ffe98f42396.png)
(1)试将桥的总造价表示为
的函数
;
(2)为使桥的总造价最低,试问这座大桥中间(两端桥墩
、
除外)应建多少个桥墩?
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/28743c3ddd979fecbf05aa55490d2493.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f52a58fbaf4fea03567e88a9f0f6e37e.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/0efba7147f5b9ced8bc4a72f0a9fb8af.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/a254ec7a18213fc8235cb6154520e34d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/b7af820f200c0bce3131184c20adc82d.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/77191cbfe81edc042f382885e1821a5c.png)
![](https://img.xkw.com/dksih/QBM/2015/7/30/1572198128050176/1572198134079488/STEM/751580b6358f4eff81f05ffe98f42396.png)
(1)试将桥的总造价表示为
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/81dea63b8ce3e51adf66cf7b9982a248.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/4fe7d5809da02c15a43a0e9a898b9086.png)
(2)为使桥的总造价最低,试问这座大桥中间(两端桥墩
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5963abe8f421bd99a2aaa94831a951e9.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7f9e8449aad35c5d840a3395ea86df6d.png)
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