关于∞ / ∞未定式L’Hospital法则的一个注记
A Note on L’Hospital Rule of Indeterminate Form ∞ / ∞

L’Hospital法则是求解极限问题中未定式的一种经典而有效的方法。本文从未定式常见类型∞ / ∞出发，研究了一类拓展型未定式？ / ∞，在一定条件下将L’Hospital法则进行了推广，给出了广义L’Hospital法则。
L’Hospital rule is a classical and effective method to solve indeterminate form in limit problem. This paper studies a class of extended indeterminate form ？ / ∞ based on common indeterminate form ∞ / ∞, generalizes L’Hospital rule under certain conditions and obtains generalized L’Hospital rule.