1本单元重、难点分析本单元的重点是:三角函数的图象和性质;周期函数与函数奇偶性的概念;已知三角函数值求角.要会用正弦线、正切线画出正弦函数、正切函数的图象,并由诱导公式画出余弦函数的图象,在此基础上,要正确理解周期函数与最小正周期的意义,通过图象理解正弦、余弦、正 1 Unit weight and difficulty analysis The key points of this unit are: the image and nature of the trigonometric function; the concept of the periodic function and the function parity; the known angle of the trigonometric function. To draw a sine function with a sinusoidal line and tangent line The image of the tangent function is drawn from the induced formula and the image of the cosine function is drawn. Based on this, the meaning of the periodic function and the minimum positive period is to be correctly understood, and the sine, cosine, and positive are understood through the image.