2014年北京中考卷压轴题一如前几年,安排了一道新定义类考题,原创引领,简洁表达,数形互动,步步向上,易进难深入,数学味浓,是一道优秀的数学试题.下面给出该题的思路探究与解后反思,启发同学们思考.例题(2014·北京)对某一个函数给出如下定义:若存在实数M>0,对于任意的函数值y,都满足-M≤y≤M,则称这个函数是有界函数,在所有满足条件的M中,其最小值称为这个函数的边界值.例如, 2014 Beijing exam rehearsal questions as a few years ago, arranged a newly defined class exam questions, original lead, concise expression, interactive digital, step by step, easy to enter the difficult, mathematical taste is a good math test The following is a reflection of the problem of thinking and reconsideration after reflection to inspire students to think.Example (2014 · Beijing) gives a definition of a function as follows: If there is a real number M> 0, for any function value y, satisfy -M ≤ y ≤ M, then call this function a bounded function, the minimum in all M that satisfies the condition is called the bounded value of this function.For example,