1)A1,A2,A3面积=(1/4+9/4)*2/2-{(1/4+1)*1/2+(1+9/4)*1/2}=1/4
抛物线给成Y=1/4X²-1/2X+2时,y1=7/4、y2=2、y3=11/4
A1,A2,A3面积=(y3+y1)*2/2-(y1+y2)*1/2-(y2+y3)*1/2=1/4
抛物线给成Y=AX²+BX+C(A>0)时,y1=A+B+C、y2=4A+2B+C、y3=9A+3B+C
A1,A2,A3面积=(y3+y1)*2/2-(y1+y2)*1/2-(y2+y3)*1/2=A