令y=0,得
x^2-x=0
y＝x^2－x与x轴的交点为
(0,0),(1,0)
所以
面积=∫(0,1)[0-(x^2-x)]dx
=∫(0,1)(-x^2+x)dx
=(-x^3/3+x^2/2)|(0,1)
=1/2-1/3
=1/6