一、欧拉的定义1748年数学英雄欧拉(L.Euler,1707～1783)的传世名著《无穷小分析引论》发表.他提出了沿用至今的三角函数的经典定义,使三角学进入了一个新的历史时期.设任意角α的顶点O为原点,始边在x轴的正半轴上,终边上任意一点P的坐标为(x,y),点P到 First, the definition of Euler Euler (L.Euler, 1707 ~ 1783) handed down in 1748 the masterpiece “Infinitely small analysis Introduction” published. He proposed the classical definition of the trigonometric function used so far, so that trigonometry has entered a In the new historical period, set the vertex O of the arbitrary angle α to be the origin, the starting edge to the positive axis of the x-axis, and the coordinate of the arbitrary point P on the terminal edge to (x,y), point P to