题目

找出P和Q的值并使得x→∞ 时f(x)=(px^2-2)/(x^2+1)+3qx+5有无穷小

提问时间：2021-04-07

答案

∵ lim(x→∞) (px^2-2)/(x^2+1)+3qx+5 = 0∴① 0 = lim(x→∞) { (px^2-2)/(x^2+1)+3qx+5 }/x = lim(x→∞) (px-2/x)/(x^2+1)+3q +5/x= lim(x→∞) (p/x-2/x^3)/(1+1/x^2) + 3q + 5/x = 0 + 3q + 0=3q∴ q = 0②∵...