高数数列极限

xn(xn^2+2)=-1/n => |xn(xn^2+2)|<ε 对n>N,ε为任意小量 => |xn|<ε/(xn^2+2)<ε/2 => lim xn = 0n*xn(xn^2+2)=-1 => n*xn=-1/(xn^2+2) => lim x*xn = -1/2