来，看看这道题目

是不是要列一个方程式，然后求极限值啊，这只是一个思路哦

d theta 是 dθ 对吧
我明白了。 Int (exp(-r^2 / 2) rdr 从0到+无穷 ＝ 1
Int (d theta) 从0到2π ＝ 2π
然后就是答案了

楼上的真强啊～～～

请问你是大学几年纪啊。因为我还没有学到把积分自乘 然后转换到解析几何，这个思路实在巧妙。

我觉得答案是应该和存钱的总天数有关系的，所以此题没有一个固定的答案。

看了半天！！答案：应该是无解。

引用

最初由 aaabbbccc 发布

with a long enough time, the winner will emerge clearly with ur question though. it's surely not a fixed number for different precondition, that's why i think ppl give out a number without even consider the precondition funny.
regardless to whatever precondition, i think e, the most efficient number in the universe, is the essential part of the answer as this whole thing is n/N >=logf(n)/logf(N). visually, it's a log curve always below a straight line.(the differential may not be)

I don't understand where the n/N >= log f(n) / log f(N) comes from. Also why is e the most efficient number? efficient in what sense? I haven't studied maths for a while, so forgive me if I'm asking silly questions.
All I managed to get is 100000*(1+(m-3))^(n/m) = amout at maturity. Where can I go from there

引用

最初由 ambivalence 发布


I don't understand where the n/N >= log f(n) / log f(N) comes from. Also why is e the most efficient number? efficient in what sense? I haven't studied maths for a while, so forgive me if I'm asking silly questions.
All I managed to get is 100000*(1+(m-3))^(n/m) = amout at maturity. Where can I go from there

faint, this problem seems keep come to the surface and refuses to die.

if u take n*N days, u will get that equation. if N is the answer then f(n)^N<=f(N)^n , f(x) is the equation for 1 round with x days. and the initial value doesnt really matter here unless the bank has some charge per day.


btw, this whole thing is a variation of n/N >=log(n)/log(N) and the answer for that is N=e. (1/N is the derivative of log(n)/log(N) when n==N, it can be seen more clearly on a graph)


e is the most efficient number is refering to if a number system is base e, u will need minimun symbols(states) to store a number in general (it's actrually the same problem as the one above). in computer, it means base 3 is most efficient for storing data, base 2 is not that bad also. anything else will waste a lot of states in general.

引用

最初由 ThunderBird 发布
做不来

真的有答案吗？好象无解的说。