You can Download Samacheer Kalvi 9th Maths Book Solutions Guide Pdf, Tamilnadu State Board help you to revise the complete Syllabus and score more marks in your examinations.
Tamilnadu Samacheer Kalvi 9th Maths Solutions Chapter 6 Trigonometry Ex 6.2
Question 1.
Verify the following equalities:
(i) sin2 60° + cos2 60° = 1
(ii) 1 + tan2 30° = sec2 30°
(iii) cos 90° = 1 – 2 sin2 45° = 2 cos2 45° – 1
(iv) sin 30° cos 60° + cos 30° sin 60° = sin 90
Solution:
Question 2.
Find the value of the following:
Solution:
Question 3.
Verify cos 3A = 4 cos3A – 3 cos A, when A = 30°
Solution:
L.H.S = cos 3A = cos 3(30°) = cos 90° = 0
R.H.S = 4 cos3A – 3 cos A = 4 cos330° – cos 30°
(1) = (2). Hence it is verified.
Question 4.
Find the value of 8 sin 2x cos 4x sin 6x, when x = 15°
Solution:
8 sin 2(15°).cos 4(15°).sin 6(15°)