a****n
发帖数: 121 | 1 we have a rv x which is distributed exponentially P(5
(10
I know we should solve (e^(-5t)) - e^(-10t) = .25 to get t, then calculate
(e^(-10t)) - e^(-20t)
but my calculation is poor. can anyone help? |
a****n
发帖数: 121 | 2 答案是1/8么？
P
calculate
【在 a****n 的大作中提到】
: we have a rv x which is distributed exponentially P(5: (10: I know we should solve (e^(-5t)) - e^(-10t) = .25 to get t, then calculate
: (e^(-10t)) - e^(-20t)
: but my calculation is poor. can anyone help?
|
s********0
发帖数: 2625 | |
k*******a
发帖数: 772 | 4 i got 3/16
if x~exp(a)
exp(-5/a)-exp(-10/a)=.25, let exp(-5/a)=x then x-x^2=.25
solve to get x=0.5
then exp(-10/a)-exp(-20/a)=x^2-x^4=3/16 |
d******e
发帖数: 7844 | 5 let X=e^(-5t), then e^(-10t) = (e^(-5t))^2.
Rewrite the equation as X - X^2 = 1/4, easy to get X = 1/2.
Therefore, e^(-10t) - e^(-20t) = X^2 - X^4 = 1/4 - 1/16 = 3/16.
P
calculate
【在 a****n 的大作中提到】
: we have a rv x which is distributed exponentially P(5: (10: I know we should solve (e^(-5t)) - e^(-10t) = .25 to get t, then calculate
: (e^(-10t)) - e^(-20t)
: but my calculation is poor. can anyone help?
|
d******e
发帖数: 7844 | 6 ... ...这东西不是拍脑门想出来的... ...
【在 a****n 的大作中提到】
: 答案是1/8么？
:
: P
: calculate
|
D******n
发帖数: 2836 | 7 被头几楼的雷倒。。。
【在 d******e 的大作中提到】
: ... ...这东西不是拍脑门想出来的... ...
|
