0 1. What does the crime of mathematics mean?

Mathematically, sine refers to the sine in a right triangle, and the ratio of the opposite side to the hypotenuse of ∠ α (non-right angle) is called the sine of ∠α, which is recorded as sinα, and the sine is the hook-chord ratio. That is, the "string" in the ancient "three strands, four strings and five" is the hypotenuse in the right triangle. A thigh is a person's thigh. The ancients called the longer right side of a right triangle "thigh". Trigonometric function is a kind of transcendental function in elementary function in mathematics.

Their essence is the mapping between the set of arbitrary angles and a set of ratio variables. The usual trigonometric function is defined in the plane rectangular coordinate system, and its domain is the whole real number domain.

02. Comparison of advantages and disadvantages of sine definition in junior high school and senior high school.

1. It is convenient to solve the sine value by using the junior middle school sine definition, but only a few special acute angles can be solved. For example, sine values of angles of 30, 45 and 60.

2, the definition of high school sine, as long as you find the coordinates of the intersection of the angle terminal edge and the unit circle, you can get the sine value of this angle immediately. But in general, it is better to use the "contrast oblique" of the right triangle in junior high school to draw and solve it conveniently.