1题x^n(x^n+1-x-1)
=x^2n+x^n-x^(n-1)
2题8^90*(1/2)*90*(1/2)*180看不明白
=
3题(-x)^3(-y)^2-(-x^3y^2)
=-x^3y^2+x^3y^2
=0第2题我打错了，是8^90*(1/2)^90*(1/2)^1808^90*(1/2)^90*(1/2)^180=2^270*2^(-90)*2^(-180)=2^(270-90-180)=2^0=1