SOLUTION
1. Evaluate the following : (i) sin 60° cos 30° + sin 30° cos 60° (ii) 2 tan2 45° + cos2 30° – sin2 60° (iii) ${cos 45° }/{sec 30° + cosec 30° }$ (iv) ${sin 30° + tan 45° – cosec 60°}/{sec 30° + cos 60° + cot 45°} $ (v) ${5 cos^2 60° + 4 sec^2 30° − tan^2 45°}/{sin^2 30° + cos^2 30°}$ 2. Choose the correct option and justify your choice : (i) ${2 tan 30°}/{1 + tan^2 30°} =$ (A) sin 60° (B) cos 60° (C) tan 60° (D) sin 30° (ii)${1 − tan^2 45° }/{1 + tan2 45°} =$ (A) tan 90° (B) 1 (C) sin 45° (D) 0 (iii) sin 2A = 2 sin A is true when A = (A) 0° (B) 30° (C) 45° (D) 60° (iv) ${2 tan 30°}/{1 − tan^2 30°}$= (A) cos 60° (B) sin 60° (C) tan 60° (D) sin 30° 3. If tan (A + B) = √3 and tan (A – B) =$1/√3$ ; ; 0° < A + B ≤ 90°; A > B, find A and B. 4. State whether the following are true or false. Justify your answer. (i) sin (A + B) = sin A + sin B. (ii) The value of sin θ increases as θ increases. (iii) The value of cos θ increases as θ increases. (iv) sin θ = cos θ for all values of θ. (v) cot A is not defined for A = 0°.