Radian Measure (Edexcel A-Level Mathematics): Flashcards

An angle subtended by an arc equal to the radius.

$2\pi$ radians equal a full angle of $360$ degrees.

Radians = Degrees × $\frac{\pi}{180}$.

Degrees = Radians × $(180/\pi)$.

$s = r\theta$, where $r$ is radius and $\theta$ is in radians.

A = (1/2)r²θ, where r is radius and θ is radians.

$\frac{\pi}{6}$ radians.

$\frac{\pi}{2}$ radians.

Used in trigonometry, physics, and circular motion.

More natural for derivatives/integrals of trig functions.