1　本单元知识网络三角函数的图象和性质分别从“形”和“数”不同的侧面反映出三角函数的变换规律 ,形数对照 (三角函数的所有性质都能在图象上反映出来 ;反之 ,通过图象进一步熟悉各种性质 ) .相得益彰 ,该单元的主要知识系统为 :1 )正弦函数、余弦函数、正切函数的图象 ,两 1 The trigonometric functions of this unit are reflected in the images and properties of trigonometric functions from the different sides of the “shape” and “number”, respectively, and the shape number comparison (all the properties of the trigonometric functions can be reflected in the image; On the contrary, through the image to further familiarity with various properties). To complement each other, the main knowledge system of this unit is: 1) The image of sine function, cosine function, tangent function, two