In physics, a lot of periodic phenomena can be simulated by trigonometric functions, such as simple harmonic vibration, tides, etc., and the model of trigonometric functions can be established, and the related properties of trigonometric functions can be used to solve the related problems. In seeking the image of trigonometric functions generally given analytical formula, by the various parameters in the analytical formula, you can get all kinds of information in the middle of the image, and then draw the image.