2重积分中 不是有那个求转动惯量的嘛...比如说Ix=∫∫y^2 *f(x,y)d6 =∫dx∫y^2 f(x,y)dy

变换积分次序∫(0,1)dy∫(-y,1+y^2)f(x,y)dx 交换累次积分的次序∫（0>1) dy∫(0>2y) f(x,y)dx +∫(1>3) dy∫(0>3-y) f(x,y) 交换二次积分的积分顺序 ∫(2,0)dx ∫(x^3,0)f(x,y)dy= 交换积分次序∫(0,1)dy∫(0,y)f(x,y)dx+∫(1,2)dy∫(0,2-y)dxf(x,y)dx 交换积分次序 ∫(4,0)dx∫(x,2x^0.5)f(x,y)dy 更换积分次序∫(0,2)dx∫(x,3x)f(x,y)dy 交换积分次序∫(1,0)dx∫(x,0)f(x,y)dy+∫(2,1)dx∫(2-x,0)f(x,y)dy 交换积分次序：∫(0,1/2)dx∫(x,1-x)f(x,y)dy= ∫[0,1] dx∫[-x^2,1] f(x,y)dy交换积分次序 交换积分次序,∫(上限2,下限0)dy∫(上限2y,下限y^2)f(x,y)dx 改变二次积分的积分次序求积分.∫1 2 dx ∫（2-x）~（√2x-x^2）f（x,y）dy 改变二次积分的积分次序求积分.∫1 ~2 dx ∫（2-x）~（√2x-x^2）f（x,y）dy