Radiant jade-like stone [? re？ di？ N] beauty [? re？ di？ n]
Radiant;
[Example] The vibration power transmission and reflection coefficient is determined as? Radian? Frequency and coupling? Angle.
The reflection and propagation coefficients are determined as functions of vibration frequency and coupling angle.
Extended data:
In mathematics and physics, radian is the unit of measurement of angle. It is a unit derived from the international system of units, abbreviated as rad. Definition: an arc whose arc length is equal to the radius and whose central angle is 1 radian. (that is, two rays shoot from the center of the circle to the circumference, forming an arc with an angle opposite to the angle. When the arc length is exactly equal to the radius of the circle, the radian of the included angle between two rays is 1).
According to the definition, the number of radians in a week is 2πr/r=2π, and the 360-degree angle =2π radians.
So 1 radian is about 57.3, that is, 57 17' 44.806'', 1 radian is π/ 180 radian, the approximate value is 0.0 1745 radian, the fillet is 2π radian, and the right angle (that is,
In the concrete calculation, when the angle is given in radians, the radian unit is usually not written, but the numerical value is written directly. The most typical example is trigonometric function, such as sin 8π, tan (3π/2).
In junior high school mathematics, we learned the formula of arc length:
Arc length =nπr/ 180, where n is the number of angles, that is, the arc length corresponding to the central angle n.
But if we use radians, the above formula will become simpler: (note that radians are positive and negative)
References:
Baidu encyclopedia-radian