用“五点法”作三角函数ｙ =Ａｓｉｎ(ωｘ + φ) (Ａ0 ,ω 0 )的图象是三角函数的重要内容 ,其中心是通过整体换元的思想求关键点的坐标 .而已知三角函数的图象求其表达式的问题 ,恰恰是已知某些关键点的坐标 ,因此 ,可视为作图问题的逆问题 .作函数 ｙ =Ａｓｉｎ(ωｘ + φ Using the “five-point method” as the trigonometric function y =Asin(ωx + φ) (A0, ω 0) is an important part of the trigonometric function, and its center is to find the coordinates of the key point through the idea of ​​integral change. The problem of finding the expression of a trigonometric function is precisely knowing the coordinates of some key points. Therefore, it can be regarded as an inverse problem of the graphing problem. As a function y = Asin(ωx + φ