取字丁豪機率講義(上)
4-42 範例33 @ 交大的題目
題目是這樣的:
Given that the joint pdf of random variables X and Y is:
fxy(x,y)={ k -1<=x<=0 ,0<=y<=2 ,solve the value of K
{ 0 elsewhere
and the pdf of random variable Z=X-Y.
k只要把雙重機分上下限代入,很快就可以得解.
我想問的是: 以下fz(Z)的積分上下限,所代的值...
積分探針 是要對x用?還是y 還有棒槌.......拜託高手了~
Fz(Z):
1/2 [2 - 1/2*Z^2] ,-1<= Z <0
1/2 [2 - 1/2*Z^2 + 1/2(Z+1)^2] ,-2<= Z <-1
1/2 [1/2 *(Z+3)^2] ,-3<= Z <-2
0 ,Z<-3;Z >=0
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