论文部分内容阅读
由圆的知识可知,直径所对的圆周角等于90°.我们将用圆的性质和韦达定理把看似没有关系的圆和二次函数联系起来.下面的两个结论在初中数学中很常见,证明方法也很多(如勾股定理,两直线垂直的判定等等).但是我们从圆角度来解释这一现象,显得非常简单,体现了数学追求“简—易—美”.结论 1已知二次函数y=ax2+bx+c的图象与x轴交于A,B两点,与y轴交于C点,则△ABC是直角
From the knowledge of the circle, the angle of the circle to the diameter equals 90. We will relate the seemingly unrelated circle to the quadratic function with the Vedic theorem by the nature of the circle. The following two conclusions are very common in junior high math Common, there are many ways to prove (such as the Pythagorean theorem, the two vertical lines of judgment, etc.) However, we explain this phenomenon from a circular angle, it is very simple, embodies the mathematical pursuit of “Jane - easy - the United States.” Conclusion 1 known quadratic function y = ax2 + bx + c image and the x-axis intersection at A, B two points, and y-axis intersection at point C, then △ ABC is a right angle