如图 1所示 ,函数 y=f(x)在区间 [a,b]上连续变图 1化 ,且 f(a)与 f(b)异号 ,那末 ,在区间 [a,b]上至少存在一点 c,使 f (c) =0成立 .这就是关于连续函数的零点定理 .一、零点定理的正向应用根据物理量在某一闭区间上连续变化、两端异号的条件 ,判断该物理量的零点 ,属于零点定 As shown in Fig. 1, the function y=f(x) is continuously transformed into a graph in the interval [a,b], and f(a) and f(b) are not equal, then in the interval [a,b]. There is at least a point c that holds f(c) = 0. This is the zero point theorem for continuous functions. The positive application of the zero point theorem is based on the condition that the physical quantity changes continuously within a closed interval and the two ends have different signs. The zero point of this physical quantity belongs to zero point