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【OG20-P166-129题】
According to a certain estimate, the depth N(t), in centimeters, of the water in a certain tank at t hours past 2:00 in the morning is given by N(t)=−20(t−5)2 + 500 for 0 ≤ t ≤ 10. According to this estimate, at what time in the morning does the depth of the water in the tank reach its maximum?
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题目:据估算,某水槽中的水深(单位为厘米)N(t)在凌晨2点以后t小时
可表示为N(t)=-20(t-5)2+500,其中0≦t≦10.问根据这种估算,早上几点钟水槽中的水深达到最大值?
解:N(t)=-20(t-5)2+500=500-20(t-5)2,(t-5)2≧0,因此要使N(t)最大,则t应取值5,所以水深在2:00以后5个小时达到最大,即早上7:00.
题目讨论 (2条评论)

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373961gg
t是2:00过后的t个小时,不是具体的时间!!= =
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0 回复 2020-05-19 10:46:49
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emily666
考的就是个概念啊。。。又想复杂了
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0 回复 2020-04-02 18:28:03