📐

Trigonometry

Trigonometric identities, equations, inverse functions, and applications

Key Concepts
  • Fundamental identity sin²θ + cos²θ = 1 and its variants
  • Compound, multiple and half-angle formulae
  • General solutions of trigonometric equations
  • Inverse trigonometric functions and their domains
  • Sine and cosine rules for solving triangles
Important Formulae
Compound angle sin(A±B) = sinA cosB ± cosA sinB
Double angle cos2A = 1 − 2sin²A = 2cos²A − 1
Tangent sum tan(A+B) = (tanA + tanB)/(1 − tanA tanB)
Sine rule a/sinA = b/sinB = c/sinC
Cosine rule c² = a² + b² − 2ab cosC
Quick Tips
  • General solution: sinθ = sinα → θ = nπ + (−1)ⁿα.
  • cosθ = cosα → θ = 2nπ ± α; tanθ = tanα → θ = nπ + α.
  • Always check the domain when working with inverse trig functions.
Sample Practice Questions

  1. The value of sin 30° is:

    • 1/2
    • √3/2
    • 1
    • 0
    Show answer

    Answer: 1/2

  2. The value of tan 45° is:

    • 0
    • 1
    • √3
    • 1/√3
    Show answer

    Answer: 1

  3. The value of sin 90° is:

    • 0
    • 1/2
    • 1
    • √3/2
    Show answer

    Answer: 1

  4. The value of cos 0° is:

    • 0
    • 1
    • 1/2
    • √3/2
    Show answer

    Answer: 1

Practise more questions →
Practice Questions

Practise randomly selected JEE questions on Trigonometry. Answers are revealed after each question.

Start Practice →
Mathematics Topics