近来一些文章和资料(包括教材)在研究函数时,常出现不注意区间端点的情况。 1.关于函数的增减性和不等式 例如有这样的叙述:欲证明不等式f(x)>g(x)在(a,b)上成立,可证明y=f(x)-g(x)在(a,b)上是增函数,并且有f(a)-g(a)≥0。(《北京市中学高中数学总 Recently, some articles and materials (including textbooks) often appear without paying attention to the interval endpoints when studying functions. 1. As for the increase and decrease of functions and inequalities, for example, there is such a narrative: To prove that the inequality f(x)>g(x) holds on (a,b), it can be proved that y=f(x)-g(x) It is an increasing function on (a,b), and there is f(a)-g(a)≥0. ("Beijing Middle School High School Mathematics Master