1/4
考查几何概型.
P=d/D.
D:0≤X≤1
0≤y≤1
d:|x-y|≥1/2
画出图像,求出面积.
S1=1x1=1
S2=2*(1/2*(1-1/2)*1/2)=1/4
概率P=S2/S1
=1/4
=0.25