若不论x取何值时,多项式(x^3)-(2x^2)-4x-1与x(x^2+mx+n)+2(mx-1/2)都相等,求m,n的值.
后一式即x^3+mx^2+(n+2m)x-1=0.对比知,m=-2,n+2m=-4,n=0.