limits and conjectures

Quote:

Originally Posted by friday616

Let P and Q be polynomials and consider the limit of P(x)/Q(x) as x approaches infinity. State and prove a conjecture for the value of this limit that depends on the degrees of P and Q and their leading coefficients.

Let $P=p_n x^n+p_{n-1}x^{n-1}+...+p_1 x+p_0$ and let $Q=q_m x^m+q_{m-1}x^{m-1}+...+q_1 x+q_0$ .

If $deg(P)>deg(Q)$ , then $\lim_{x\to\infty}\frac{P(x)}{Q(x)}=\infty$ .

If $deg(P)<deg(Q)$ , then $\lim_{x\to\infty}\frac{P(x)}{Q(x)}=0$ .

If $deg(P)=deg(Q)$ , then $\lim_{x\to\infty}\frac{P(x)}{Q(x)}=\frac{p_n}{q_m}$ .

The proofs are fairly straightforward. If $k=\min\{n,m\}$ , just factor out $x^k$ from both polynomials and see what you have left.