作者LuisSantos (^______^)
看板trans_math
标题Re: [考古] 东吴92商数
时间Sat Jul 8 19:23:07 2006
※ 引述《frde (蒙其D鲁夫)》之铭言：
: x f(t)
: 3. 6 + ∫ ______ dt = 2X^1/2
: a t^2
: 求 a = ?
: 6.
: Use Lagrange multipliers to maximize f(x,y,z)=x+y+z subject to
: 1 1 1
: -- + -- + -- = 1
: x y z
3. 两边对 x 微分
f(x) 1 3
------ = ----- => f(x) = x^(---) 代回原方程式
x^2 √x 2
x t^(3/2)
6 + ∫ --------- dt = (2)(x^(1/2))
a t^2
x
∫ t^(-1/2) dt = (2)(x^(1/2)) - 6
a
|x
(2)(t^(1/2)) | = (2)(x^(1/2)) - 6
|a
(2)(x^(1/2)) - (2)(a^(1/2)) = (2)(x^(1/2)) - 6
a^(1/2) = 3 => a = 3^2 = 9
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 61.66.173.21
1F：推 frde:感谢 218.167.45.66 07/08 19:27