Selina Concise Mathematics Class 9 ICSE Maths Solutions Chapter 23 - Trigonometrical Ratios of Standard Angles
Selina Concise Mathematics Class 9 ICSE Solutions Trigonometrical Ratios of Standard Angles Selina ICSE Solutions for Class 9 Maths Chapter 23 Trigonometrical Ratios of Standard Angles [Including Evaluation of an Expression Involving Trigonometric Ratios] Exercise 23(A) 1. find the value of: ( i ) sin 30 o cos 30 o (ii) tan 30 o tan 60 o (iii) cos 2 60 o + sin 2 30 o (iv) cosec 2 60 o - tan 2 30 o (v) sin 2 30 o + cos 2 30 o + cot 2 45 o (vi) cos 2 60 o + sec 2 30 o + tan 2 45 o . Solution 1: 2. find the value of : ( i ) tan 2 30 o + tan 2 45 o + tan 2 60 o (ii) (iii) 3 sin 2 30 o + 2 tan 2 60 o - 5 cos 2 45 o . Solution 2: 3. Prove that: ( i ) sin 60 o cos 30 o + cos 60 o . sin 30 o = 1 (ii) cos 30 o . ...