Ch 03 -Trigonometric Functions — Chapter Summary

An angle is formed by two

An angle is formed by two rays with a common end-point. The common point is the vertex, and the rays are the initial side and terminal side. Anticlock

A degree is 1/360 of

A degree is 1/360 of a revolution. A radian is the angle subtended at the centre of a circle by an arc equal in length to the radius. The relation is

If a circle has radius r

If a circle has radius r and central angle θ in radians, then arc length is l = rθ and sector area is A = (1/2)r²θ.

For a point P(a

For a point P(a,b) on the unit circle, with angle x measured from the positive x-axis, sin x = b and cos x = a. Then tan x = sin x / cos x, cot x = co

sin x and cos x

sin x and cos x are defined for all real numbers and have range [-1,1]. tan x is undefined where cos x = 0, i.e. at odd multiples of π/2. cot x and co