30
fx(x)=∫(0~) f(x,y)dy=1
fy(y)=∫(0~1)f(x,y)dx=e^(-y/2)/2
fx(x)fy(y)=f(x,y)所以互相独立
31
1)
x>=1时
Fx(x)=∫(1~x) 1/t² dt
=1-1/x
Fx(x)=1-1/x(x>=1)
=0(x
30
fx(x)=∫(0~) f(x,y)dy=1
fy(y)=∫(0~1)f(x,y)dx=e^(-y/2)/2
fx(x)fy(y)=f(x,y)所以互相独立
31
1)
x>=1时
Fx(x)=∫(1~x) 1/t² dt
=1-1/x
Fx(x)=1-1/x(x>=1)
=0(x