积分区域为：y=x^2，y=x，0<=x<=1围成的区域令x=rcosθ，y=rsinθ由y=x^2，得：rsinθ=r^2*cos^2θsinθ=rcos^2θr=sinθ/cos^2θ由y=x，得：rsinθ=rcosθtanθ=1θ=π/4所以0<=θ<=π/4，0<=r<=sinθ/cos^2θ
