Related InterviewSolutions

• Prove that:(i) 2 sin 5π/12 sin π/12 = 1/2(ii) 2 cos 5π/12 cos π/12 = 1/2(iii) 2 sin 5π/12 cos π/12 = (√3 + 2)/2
• The value of sin 78° – sin 66°– sin 42°+ sin 6°is A. 1/2 B. -1/2 C. -1 D. None of these
• If sin α + sin β = a and cos α – cos β = b, then tan(α - β)/2 = A. - (a/b)B. - (b/a)C. √(a2+b2)D. None of these
• cos 40°+ cos 80°+ cos 160°+ cos 240 °= A. 0 B. 1 C. 1/2 D. -1/2
• Prove that :(i) sin 38° + sin 22° = sin 82°(ii) cos 100° + cos 20° = cos 40°
• The value of sin 50° – sin 70°  + sin 10° is equal to A. 1 B. 0 C. 1/2 D. 2
• Prove that:(i) cos 3A + cos 5A + cos 7A + cos 15A = 4 cos 4A cos 5A cos 6A(ii) cos A + cos 3A + cos 5A + cos 7A = 4 cos A cos 2A cos 4A(iii) sin A + sin 2A + sin 4A + sin 5A = 4 cos A/2 cos 3A/2 sin 3A