推荐回答（1个）
其实这是一个很简单的数学问题。 首先你要搞清楚这个弹性问题的概念。经济学家们用即这个概念的时候，一般只是判断这个商品，它的需求弹不弹性。比如说石油需求的价格弹性数值小于1，说明它不弹性，一定量的价格上涨，会带来少量的需求量下降。大于一，说明是弹性的。 当它的数值等于一的时候，说明一定百分比的价格变化，会带来相同百分比的需求量变化。
你举的例子，由于数字看上去好像跟理论不符，其实不然。这是一个经济学家们也提到过的问题。 这个问题的关键在于，当我们分析出来弹性这个概念的时候，所分析的需求曲线，是线性关系的，是一条直线，很简单的数学关系，所有的数学公式，关系都成立。 斜度大于一的时候，需求是弹性的，等于一的时候，总收入（曲线下面的面积）不变，斜度小于一的时候，需求不是弹性的。 可是在普遍情况下，需求曲线都不是直线，都是曲线，他的斜度在不停地变化。所以才得到你例子当中最后结果的不统一。 其实概念都是一样的。 在这种情况下，经济学家们通常的做法是，把需求的价格弹性定义改成研究价格的很小的变动，这种小的变动在曲线上呈现出来的是很小的斜度变化（类似于微分） 这样就让研究的结论更接近与直线需求。这样一来，即使需求是曲线，价格弹性的概念还是可以运用。 恩 差不多了，希望能让你明白一些。我建议你多去看看其他的教科书什么的，把基本的定义搞清楚，数字它只是数字，经济学家毕竟不是数学家，你首先得明白这个概念的意义在哪里，然后再去小心地求证。
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