Citation:
A radian is a unit of angular measure used in mathematics, defined as the angle subtended at the center of a circle by an arc whose length is equal to the radius of the circle. This measure connects directly to the concept of circular motion and trigonometric functions, serving as a bridge between linear and angular measurements. Using radians simplifies many mathematical formulas, particularly in calculus and trigonometry, making it essential for understanding angles and their relationships in various contexts.