谢谢了,expr = expand((w1+w2)^3*(w1*(u1+v1)*(u2+v2)*(u3+v3)*(u4+v4)+w2*v1*v2*v3*v4)-(w1+w2)^2*[(w1*(u1+v1)*(u2+v2)*(u3+v3)+w2*v1*v2*v3)*(w1*(u4+v4)+w2*v4)+(w1*(u2+v2)*(u3+v3)*(u4+v4)+w2*v2*v3*v4)*(w1*(u1+v1)+w2*v1)]-(w1+w2)^2*[(w1*(u1+v1)*(u2+v2)+w2*v1*v2)*(w1*(u3+v3)*(u4+v4)+w2*v3*v4)]+(w1+w2)*[(w1*(u1+v1)*(u2+v2)+w2*v1*v2)*(w1*(u3+v3)+w2*v3)*(w1*(u4+v4)+w2*v4)+(w1*(u2+v2)*(u3+v3)+w2*v2*v3)*(w1*(u1+v1)+w2*v1)*(w1*(u4+v4)+w2*v4)+(w1*(u3+v3)*(u4+v4)+w2*v3*v4)*(w1*(u1+v1)+w2*v1)*(w1*(u2+v2)+w2*v2)]-(w1*(u1+v1)+w2*v1)*(w1*(u2+v2)+w2*v2)*(w1*(u3+v3)+w2*v3)*(w1*(u4+v4)+w2*v4))