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函数的单调性是函数的重要性质之一 ,平时的教学中我们对于证明函数的单调性 ,求函数的单调区间比较熟悉 ,但对于利用函数的单调性巧妙解题 ,却知之不多。本文归纳介绍它的一些应用 ,供参考。1 求值域例 1 求函数 ｙ=3 ｘ +2 -ｘ -7的值域。解 ｙ=3 9ｘ +2 +ｘ -7,∵ｘ +2
The monotony of the function is one of the important properties of the function. In the usual teaching, we are familiar with the monotonicity of the proof function and find the monotonic interval of the function, but we don’t know much about the monotony of the function. This article summarizes some of its applications for reference. 1 Evaluation Domain Example 1 Find the range of the function y=3 x +2 -x -7. Solution y=3 9x +2 +x -7, ∵x +2