Depending on the graph of a cubic polynomial

来源: dr_yin 于 2015-10-16 14:28:11 [] [旧帖] [给我悄悄话] 阅读数 : 0 (734 bytes)
本帖于 2015-10-16 14:41:57 时间, 由普通用户 dr_yin 编辑
回答: 跟提供的解法3类似 由 怪哉 于 2015-10-16 14:05:59

First, the solutions on AOPS site depends on the graph of a cubic polynomail. Some calculus is needed to detail the graph of a cubic polynomial.

Second, they are hard to understand, especially on which values should be positive or negative.

I gave a solution without this dependency and it is easy to explain.

I went further to find the polynomial. The polynomial does not satisfy the condition of the problem.

What is wrong with my solution?


 

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