一、新旧教材的对比1.定义的差别新教材“任意角三角函数”(人民教育出版社A版,必修4第一章),其三角函数采用如下的定义(姑且称这个定义为“单位圆定义法”):“设α是一个任意角,它的终边与单位圆交于点P(x,y),那么 First, the contrast between old and new textbooks 1. The definition of the difference New textbook ”Arbitrary angle trigonometric function“ (People’s Education Press A edition, Compulsory 4 Chapter I), the trigonometric functions using the following definition (tentatively called the definition of ”Unit circle definition method“): ”Let α be an arbitrary angle whose end is intersected with the unit circle at point P (x, y), then