你想问的问题应该是这样的吧?∫[-1--->0] dx∫[0--->x+1] f(x,y)dy+∫[0--->1] dx∫[0--->1-x] f(x,y)dy交换次序后为:∫[0--->1] dy∫[y-1--->1-y] f(x,y)dx