微积分问题2

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微积分问题2
微积分问题2

微积分问题2
Solution:
Using "cut and paste",the total amount of oil in barrels roughly = the area of 5 grids
So,[100×24]÷4×5 = 3000
Ans :D
If respect to time:
f(x) = [x²-2]/[x-1] = x + 1 - 1/[x-1]
df/dt = [1 + 1/(x-1)²]dx/dt = .
This question is imcomplete.
If respect to x:
df/dx = [1 + 1/(x-1)²]
When x = 2
df/dx = 1 + 1 = 2
The ans is also D.

答:
第一题选D,很明显是在2400和4800之间。
第二题:
f'(x)=[2x(x-1)-(x^2-2)]/(x-1)^2
=(x^2-2x+2)/(x-1)^2
f当x=2时,f'(2)=2
选D。