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一次数学测试中,有一道填空题和一道解答题:1.填空题:“若x=-x,则x满足”.学生答:x≤0.2.解答题:x是数轴上一个数,试讨论:x为有理数时,|x+1|+|x-2|是否存在最小值?若存在,求出这个最小值;若不存在,请说明理由.学生解答:不存在.因为任何数的绝对值都是非负数.如果|x+1|+|x-2|这个式子有最小值,那么这个最小值就是0;经过计算得x=-1和x=2.因为x的值不相等,所以没有最小值.根据以上情形,触发笔者的一些思考:学
A math test, there is a fill in the blank questions and a solution to the questions: 1. Fill in the blank: “If x = -x, then x satisfies ” Student Answer: x <0.2 Answer: x is a number on the axis, Try to discuss: x is a rational number, | x + 1 | + | x-2 | is there a minimum value? If present, find the minimum value; if not, please explain the reason Student’s answer: does not exist. Because any number The absolute value is nonnegative. If x + 1 | + | x-2 | has the minimum value of this formula, then this minimum is 0; x = -1 and x = 2 are calculated. Because the value of x is not Equal, so there is no minimum.According to the above situation, trigger some of my thinking: learning