NCERT Solutions Class 10 Maths Chapter 8 — Introduction to Trigonometry#

Chapter 8 introduces trigonometric ratios — sine, cosine, tangent and their reciprocals — for an acute angle in a right triangle. You will find the values of these ratios for specific angles (0°, 30°, 45°, 60°, 90°) and prove fundamental trigonometric identities.

Exercises#

• Exercise 8.1 — Trigonometric ratios of an acute angle in a right triangle (11 questions)
• Exercise 8.2 — Trigonometric ratios of some specific angles (4 questions)
• Exercise 8.3 — Trigonometric identities — prove and apply (4 questions)

What you will learn#

• The six trigonometric ratios of an acute angle in a right triangle.
• Finding all the ratios when one of them is given.
• The values of the ratios at 0°, 30°, 45°, 60° and 90°.
• Proving and using trigonometric identities.

Key formulas and results#

• $\sin^2 A + \cos^2 A = 1$
• $1 + \tan^2 A = \sec^2 A$
• $1 + \cot^2 A = \operatorname{cosec}^2 A$
• $\tan A = \dfrac{\sin A}{\cos A}$

Read and revise#

• Class 10 Maths Notes — Introduction to Trigonometry: every definition, formula and method in short.
• All Class 10 Maths formulas on one page.
• NCERT Class 10 Maths Chapter 8 (PDF) — the textbook chapter itself, and all Class 10 Maths chapters.

Frequently asked questions#