√x=2-x 解得x=1 2-x=-x/3 解得 x=3
设面积为S=∫(0,1)(√x+x/3)dx+∫(1,3)[(2-x)+x/3]dx
=2√x³+x²/6｜(0,1)+[2x-x²/2+x²/6](1,3)
=2+1/6+3-10/6=21/6