Lecture 3 (Calculus) Radians, Trig Functions, Graphs, Trig Identities, and The Law of Sin and Cos

On a circle of radius R, the arc length s subtended by an angle θ is given by:

1. A.s = R/θ, dividing the radius by the angle
2. B.s = θ/R, dividing the angle by the radius
3. C.s = 2πRθ, scaling the full circumference by θ
4. D.s = Rθ, valid only when θ is measured in radians