反三角函数为啥叫arcXXX
In the inverse trigonometric function arctan, the term arc is used because when measuring an angle in radians, the arc length of a part of the circle bisected by an angle (with the vertex at the center of the circle) equals the angle measure.
The radian is the standard unit of measurement for an angle and is equal to approximately 57 degrees (360° / 2π). It is based on the radius of a circle.
- arctan formula, arctangent fucntion, inverse tangent formula, arctan symbol
- Trigonometric and Hyperbolic inverses - 'ar' or 'arc'?
Inverse和reverse有何不同？"cars with five forward gears and a reverse" 有五个前进挡和一个倒挡的汽车
