Question

设1+2+3+…+m=p,计算x(m次方)y·x(m-1次方)·y(2次方)·…·xy(m次方),

Answer 1

1+2+3+…+m=p

x^my * x^(m-1) * y^2* x^(m-2) * y^3…* xy^m 【其中^代表乘方】

=x^{m+(m-1)+(m-2)+(m-3)+.1} y^{1+2+3+...m}

=x^py^p

=(xy)^p