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1 . 海南某橡胶工厂曾被曝光废气排放不达标,经了解,废气需要经过严格的过滤程序后排放.过滤过程中废气的污染物含量
(单位:
)与时间
(单位:
)间的关系为
,其中
,
是正的常数.如果在前
消除了20%的污染物,那么
(1)
后还剩百分之几的污染物?
(2)污染物减少百分之四十至少需要花多少时间(精确到
)?(参考数据:
)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/dad2a36927223bd70f426ba06aea4b45.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bcd47838a087313bae9c15e075fd3c20.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/36a1b09c653185842513e24ebba60bb3.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1933311c0c090e1138e4dd388b7adf8a.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/7a56bb4f2defabb80f1861b75a4607a1.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/bf9f50605db5d5f8f3a01ee8e474a112.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/f0a532e15e232cb4b99a8d4d07c89575.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/5c63f6b1652d3e830ed2dbc65253d043.png)
(1)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/ab08fbc52fe3a4ad4261256774e89904.png)
(2)污染物减少百分之四十至少需要花多少时间(精确到
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/1b29f60fc3d32ca94740f0adf3fd0b53.png)
![](https://staticzujuan.xkw.com/quesimg/Upload/formula/6545de0f9e6b5259445c2891fb2c0928.png)
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