Chapter 4 of 10
Revision Notes
Trigonometric Functions - II — Revision Notes
NIOS · Class 12 · Mathematics
Trigonometric Functions - II revision notes for NIOS Class 12 Mathematics: 4 topics in quick points. Part of the NIOS Class 12 Mathematics syllabus.
45 questions25 flashcards7 formulas & key relations5 concepts
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Key Topics to Revise
1
Addition and Subtraction Formulae
- cos(A+B) = cosA cosB - sinA sinB — this is the MASTER formula from which all others are derived
- cos(A-B) = cosA cosB + sinA sinB — replace B with -B in cos(A+B)
- sin(A+B) = sinA cosB + cosA sinB — derived using complementary angle identity
2
Product-to-Sum and Sum-to-Product Transformations
- These formulae convert products of trig functions into sums/differences and vice versa
- Product-to-Sum: 2sinAcosB = sin(A+B) + sin(A−B)
- Product-to-Sum: 2cosAsinB = sin(A+B) − sin(A−B)
3
Multiple Angle Formulae (2A and 3A)
- sin2A = 2sinAcosA = 2tanA/(1+tan²A)
- cos2A = cos²A − sin²A = 2cos²A − 1 = 1 − 2sin²A = (1−tan²A)/(1+tan²A)
- tan2A = 2tanA/(1−tan²A)
4
Sub-Multiple Angle Formulae (A/2)
- A/2, A/3, A/4 are called sub-multiples of A
- sin(A/2) = ±√((1−cosA)/2) — sign depends on the quadrant of A/2
- cos(A/2) = ±√((1+cosA)/2) — sign depends on the quadrant of A/2
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Full NotesKey Concepts
These are fundamental formulae that expressThese formulae convert products of trigonometricThe reverse transformation converts sumsThese formulae express trigonometric functionsThese formulae express trigonometric functions
Frequently Asked Questions
What are the important topics in Trigonometric Functions - II for NIOS Class 12 Mathematics?
Key topics in Trigonometric Functions - II include Addition and Subtraction Formulae, Product-to-Sum and Sum-to-Product Transformations, Multiple Angle Formulae (2A and 3A), Sub-Multiple Angle Formulae (A/2). Study these first, then practise questions on each for the NIOS Class 12 board exam.
How should I revise Trigonometric Functions - II for the NIOS Class 12 board exam?
Learn the core ideas first, then work through the 45 practice questions on Trigonometric Functions - II. Revise definitions regularly and use flashcards for quick recall before the exam.
Sources & Official References
Content is aligned to the official syllabus. Refer to the board website for the latest curriculum.
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