Chapter 6 of 8
Revision Notes
Trigonometry — Revision Notes
Tamil Nadu Board · Class 10 · Mathematics
Trigonometry revision notes for Tamil Nadu Board Class 10 Mathematics: 4 topics in quick points. Includes 1 Trigonometric Ratios - Foundation, 2.
45 questions25 flashcards6 formulas & key relations5 concepts
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Key Topics to Revise
1
6.1 Trigonometric Ratios - Foundation Concepts
- Trigonometric ratios are defined for acute angles (0° < θ < 90°) using a right-angled triangle
- Six basic trigonometric ratios: sine, cosine, tangent, cosecant, secant, cotangent
- sin θ = Opposite/Hypotenuse; cos θ = Adjacent/Hypotenuse; tan θ = Opposite/Adjacent
2
6.2 Trigonometric Ratios of Complementary Angles
- Two angles are complementary if their sum is 90°
- sin(90° - θ) = cos θ and cos(90° - θ) = sin θ
- tan(90° - θ) = cot θ and cot(90° - θ) = tan θ
3
6.3 Standard Values of Trigonometric Ratios
- Must memorize exact values for 0°, 30°, 45°, 60°, and 90° - These are asked frequently in exams
- sin 0° = 0, sin 30° = 1/2, sin 45° = 1/√2, sin 60° = √3/2, sin 90° = 1
- cos 0° = 1, cos 30° = √3/2, cos 45° = 1/√2, cos 60° = 1/2, cos 90° = 0
4
6.4 Trigonometric Identities - Proving and Simplifying
- An identity is an equation true for all valid angle values, not just specific angles
- Three fundamental identities: sin²θ + cos²θ = 1, 1 + tan²θ = sec²θ, 1 + cot²θ = csc²θ
- These identities are derived from Pythagoras theorem applied to trigonometric ratios
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Full NotesKey Concepts
For a rightThree fundamental identities form the coreTwo angles are complementary if theyStudents must memorize trigonometric ratiosThe angle of elevation is
Frequently Asked Questions
What are the important topics in Trigonometry for Tamil Nadu Board Class 10 Mathematics?
Key topics in Trigonometry include 1 Trigonometric Ratios - Foundation Concepts, 2 Trigonometric Ratios of Complementary Angles, 3 Standard Values of Trigonometric Ratios, 4 Trigonometric Identities - Proving and Simplifying. Study these first, then practise questions on each for the Tamil Nadu Board Class 10 board exam.
How should I revise Trigonometry for the Tamil Nadu Board Class 10 board exam?
Learn the core ideas first, then work through the 45 practice questions on Trigonometry. Revise definitions regularly and use flashcards for quick recall before the exam.
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