Again without appealing to the general theorem on limits of products, but using the preceding exercise, prove that if \lim _{x \rightarrow w} f(x)=L \text { then } \lim _{x

\rightarrow w} f(x)^{3}=L^{3} \text { . You can also use in your proof the identity, } a^{3}-b^{3}=(a-b)\left(a^{2}+a b+b^{2}\right) \text { . }