用來求無窮小或無窮大變量之此的極限的洛必大(G.F.de l′Hospitale)法則為我們所熟知,本文用幾何方法來證明此法則因而推廣此法則,最後並利用推廣後的法則說明它與極限論中一古典定理——施篤茲(O.S.Stolz)定理問的關係。§1. 洛必大法則的幾何證明洛必大法則有兩個,可叙述如下: 法則一如f(t)及g(t)連續於區間(a,b),且(?)而在這區間內部導數f′(t)及g′(t)都有限,且f′(t)≠0;如果(?)(有限或無窮大),則必(?) 這裹為了以後說話方便,將所有的極限都寫成了右極限,其實只要這一法則能够證明,那末 The GFde l’Hospitale law for finding the limit of infinitesimal or infinity of this variable is well known to us. This paper uses geometric methods to prove this law and thus generalizes the rule. Finally, it uses the generalized law to explain it. The relationship with the classic classical theorem of the limit theory, OSStolz theorem. §1. The Lobi’s law of Geometry proves that there are two Lop’s laws, which can be described as follows: The law is like f(t) and g(t) continuous in the interval (a,b), and (?) The internal derivatives f′(t) and g′(t) of the interval are finite, and f′(t)≠0; if (?) (finite or infinity), the bound (?) is wrapped for future convenience, and all The limits of the right are written as the right limit. In fact, as long as this law can prove, then