=-∫(1-x)^(1/2)d(1-x)
=-(1-x)^(1/2+1)/(1+1/2)
=-(2/3)*(1-x)^(3/2)
x=1,-(2/3)*(1-x)^(3/2)=0
x=0,-(2/3)*(1-x)^(3/2)=-2/3
所以原式=0-(-2/3)=2/3