lim(x→∞) (2x^2-3x-4)/(1+x^4)^(1/2)
=lim(x→∞)(2-3/x-4/x^2)/(1/x^4+1)^(1/2)
lim(x→∞)3/x=0,lim(x→∞) 4/x^2=0 lim(x→∞)1/x^4=0
=2