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# Exercise 6.2: Trigonometric Ratios of Some Special Angles

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Trigonometric Ratios of Some Special Angles

Exercise 6.2

1. Verify the following equalities:

(i) sin2 60º + cos2 60 º = 1

(ii) 1 + tan2 30º = sec2 30º

(iii) cos 90º = 1 − 2sin2 45º = 2 cos2 45º − 1

(iv) sin 30º cos 60º + cos 30º sin 60º = sin 90º

2. Find the value of the following:

(i)

(ii) (sin 90° + cos 60 ° + cos 45°) × (sin 30° + cos 0 ° − cos 45°)

(iii) sin2 30º − 2 cos3 60º + 3 tan4 45º

3. Verify cos 3A = 4 cos3 A − 3cos A , when A = 30º

4. Find the value of 8 sin 2x cos 4 x sin 6x, when x = 15º

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9th Maths : UNIT 6 : Trigonometry : Exercise 6.2: Trigonometric Ratios of Some Special Angles | Numerical Problems with Answers, Solution | Trigonometry | Maths