本文提出了一元n次方程的极限解定理和计算法则。并举例说明了这一法则在取样锁相环稳定性分析中的应用。我们在研究稳定性一类的极限解等问题时,有时会遇到当β=β_a时,a_u(β_a),a_(n-1)(β_a),…,a_1(β_a)和a_o(β_a)都等于0。方程: a_n(β)x~n+a_(n-1)(β)x~(n-1)+…a_1(β)x+a_0(β)=0是这样的一个不定式: 0x~n+0x~(n-1)1…+0x+0=0本文提出的一元n次方程的极限解法,就是着眼于研究当β→β_a时,上述方程的极限情况。 In this paper, the limit solution theorem and calculation rule of one-dimensional n-order equation are proposed. And illustrates the application of this law in the stability analysis of sampling PLL. When we study some problems such as the limit solution of stability class, we sometimes encounter a_u (β_a), a_ (n-1) (β_a), ..., a_1 (β_a) and a_o (β_a) All equal to 0. The equation: a_n (β) x ~ n + a_ (n-1) (β) x ~ (n-1) + ... a_1 (β) x + a_0 (β) = 0 is an infinitive: 0x ~ n + 0x ~ (n-1) 1 ... + 0x + 0 = 0 The limit solution of the univariate n-th equation proposed in this paper is to study the limit case of the above equation when β → β_a.