y=x²-2y=x先求交点x²-2=xx²-x-2=0(x-2)(x+1)=0得 x=2 或 x=-1∫x-(x²-2)dx=∫-x²+x+2 dx [-1,2]=-x³/3+x²/2+2x [-1,2]=(-8/3+2+4)-(1/3+1/2-2)=10/3+7/6=9/2