作业帮谁能帮我做出这道题来啊,救命Oil is pumped continuously from a well at a rate proportional to the amount of oil left in the well.Initially there were 2 million barrels of oil in the well; six years later 1,000,000 barrels remain.(a) At wha
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谁能帮我做出这道题来啊,救命Oil is pumped continuously from a well at a rate proportional to the amount of oil left in the well.Initially there were 2 million barrels of oil in the well; six years later 1,000,000 barrels remain.(a) At wha
谁能帮我做出这道题来啊,救命
Oil is pumped continuously from a well at a rate proportional to the amount of oil left in the well.Initially there were 2 million barrels of oil in the well; six years later 1,000,000 barrels remain.
(a) At what rate was the amount of oil in the well decreasing when there were 1,200,000 barrels remaining?
rate = （ ）barrels/year
(b) When will there be 100,000 barrels remaining?
after years.
这个是一个积分题，我做着都快头疼死了
谁能帮我做出这道题来啊,救命Oil is pumped continuously from a well at a rate proportional to the amount of oil left in the well.Initially there were 2 million barrels of oil in the well; six years later 1,000,000 barrels remain.(a) At wha
设存量为y,dy = kydt,所以 y = e^( kt + C ) = C * e^(kt)
y|t=0 = 2million,所以 C = 2million
y|t=6 = 1million,所以 k = -ln2 / 6
y = 2 * 10^6 * 0.5^(t/6)
其他的数据带入进去算一下就行了.
新春快乐.
1楼是对的，常微分方程，只是后面代数要用计算器
由v=dx/dt=kx，x=2-∫d(tv)/dt·dt,分步微分后分别积分得：2-x=2kxt,代入条件得k=1/12,因此v=0.1(million barrels/year).
2000000（0.5)^-6
6*lg20/lg2