lim_[x→∞]n(√(n^2+2)-n)
=lim_[x→∞](√(n^4+2n^2)-n^2)
=lim_[x→∞](√(n^4+2n^2)-n^2)(√(n^4+2n^2)+n^2)/√(n^4+2n^2)+n^2
=lim_[x→∞]2n^2/√(n^4+2n^2)+n^2
=lim_[x→∞]2/√(1+2/n^2)+1
=2/1+1
=1