《中小学数学》初中版2008年第11期刊登了一读者寻求解答一道数学题的信息,现将自己的两种解法提供给同行,以供参考.解题之前先明确一个数学定理:定理若二次函数y=ax2+bx+c,在开区间或闭区间上函数值恒为0,则在此开区间或闭区间上有a=b=c=0.(证明略)问题已知△DEF是等边三角形, “Primary and secondary mathematics” junior high school edition in 2008 eleventh published a reader seeking answers to a math problem information, now their own two solutions available to colleagues for reference. Problem-solving before a clear mathematical theorem: Theorem if The quadratic function y = ax2 + bx + c, a = b = c = 0 in the open interval or closed interval in the open interval or closed interval function value is always 0, the problem is known △ DEF is an equilateral triangle,