作者dreamenjoy (今天也很爽)
看板trans_math
标题[考古] 99中兴转考
时间Tue Apr 24 12:44:16 2012
1. Find the limit lim Σ [Sin (iπ/n)] π/n
n→∞ i=1
8.Let a1 = 4 and an+1 = 1/2(an+4/an), for n >= 1. Find lim an if it exists.
n→∞
(这题我算答案是2 不知道对不对?)
9. A store has been selling 200 DVD burners a week at $350 each.
A market survey indicates that, for each $10 rebate offered to buyers,
the number of units sold will increase by 20 a week.
(1) Find the demand (or price) function and the revenue function.
[hint: the demand function p(x) stands for the price
per unit that the company can change if it sells x units.
The revenue function is defined by R(x) = xp(x),
if the company sells x units.]
(2) How large a rebate should the store offer to maximize its revenue?
10.Suppose that a bug is located on the hyperbolic paraboloid z = y^2 -x^2
at the point (1,1,0) In what direction should it move for the steepest
climb and what is the slope as it starts out?
麻烦各位大大了 感恩~
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◆ From: 111.242.106.155
1F：→ a016258:8. YA 不过你要先证明它存在~ 114.44.177.130 04/24 12:55
2F：→ dreamenjoy:OK 那我只有其他三题有问题了111.242.106.155 04/24 13:04
3F：→ a016258:1. Riemann sum ...前几天好像才刚看到~ 114.44.177.130 04/24 13:17
4F：→ dreamenjoy:第1题解出来罗! 我剩第10题不了解111.242.112.218 04/25 01:38
5F：推 ToMoveJizz:试试看方向导数118.166.243.172 04/25 22:16
6F：→ dreamenjoy:我有想到用方向导数 但是不确定答案 114.26.174.53 04/25 22:18
7F：→ dreamenjoy:因为也没正解@@ 114.26.174.53 04/25 22:18