CBSE · Class 6-12

Class 11 · Mathematics (041)

Unit 3 · Class 11Mathematics (041)

Sets and Functions

Trigonometric Functions

Angles, radian measure, trigonometric functions, identities, and equations.

Formative-only for boards

General solutions of specific trigonometric equations

Learn these concepts — they won't appear in the CBSE 2026-27 board paper.

Lessons

4 concepts

1
Angles and Radian Measure
$180^\circ = \pi$ rad. Arc length $\ell = r\theta$ ; area of sector $= \tfrac{1}{2} r^2 \theta$ .
2
Trigonometric Functions of a Real Number
$\sin, \cos$ have period $2\pi$ ; $\tan, \cot$ period $\pi$ . Signs by quadrant (ASTC).
3
Fundamental Identities
$\sin^2\theta + \cos^2\theta = 1$ ; $1 + \tan^2\theta = \sec^2\theta$ ; $1 + \cot^2\theta = \csc^2\theta$ .
4
Sum, Difference & Multiple Angles
$\sin(A \pm B) = \sin A \cos B \pm \cos A \sin B$ ; $\cos 2A = 1 - 2\sin^2 A$ ; $\sin 3A = 3\sin A - 4\sin^3 A$ .

Skills to practise

Skill · medium

Trigonometric Functions — Practice (coming soon)

Practice bank for this unit is in progress. You can still read the lessons above.