How to define the concepts of arbitrary angle, quadrant angle, positive angle, negative angle and zero angle?

Definition:

1, any angle: the figure formed by the rotation of light around its endpoint.

2. quadrant angle: measure the horizontal angle of a straight line from the northern or southern end of the basic direction clockwise or counterclockwise.

3. Negative angle: the angle of clockwise rotation.

4. Positive angle: the angle at which the light rotates counterclockwise.

5. Zero degree angle: the angle formed by light without rotation.

Representation method:

When the starting edges of angles are the same, all angles that are the same as the ending edges of angle α, including angle α, can be expressed by k 360+α, k ∈ z or k 2π+α, K ∈ z.

Angle system: use degrees (), minutes (') and seconds (") to measure angles; Curvature system: measure the size of the angle by the size of the angle. 1/360 of rounded corners is regarded as 1 degree, so half a week is 180 degree, and one week is 360 degree.

Extended data:

Transformation relation:

A right angle is π radian. ? That is, 180 degrees = π radians;

This means:?

1 degree = π/ 180 radians (≈0.0 17453 radians)?

Therefore, the formula for converting degrees into radians is obtained:?

Radian = degree ×π/ 180?

For example:?

90 = 90× π/ 180 = π/2 radians?

60 = 60× π/ 180 = π/3 radians?

45 = 45× π/ 180 = π/4 radians?

30 = 30× π/ 180 = π/6 radians?