Let's take the limit x→−∞lim(4x3) Let's divide numerator and denominator by x^3: x→−∞lim(4x3) = x→−∞lim41x311 Do Replacement u=x1 then x→−∞lim41x311=u→0+lim(u34) = 04=−∞
The final answer: x→−∞lim(4x3)=−∞
Lopital's rule
There is no sense to apply Lopital's rule to this function since there is no indeterminateness of 0/0 or oo/oo type