Saved Bookmarks
| 1. |
Given that sin α = √3/2 and tan β = 1/√3, then the value of cos (α - β) is :(a) √3/2(b) 1/2(c) 0(d) 1/√2 |
|
Answer» Correct answer is (a) √3/2 Given, sin α = √3/2 sin α = sin 60° α = 60° tan β = 1/√3 tan β = tan 30° β = 30° ∴ cos (α - β) = cos (60° - 30°) = cos 30° = √3/2 GIVEN: sin ɑ = √3 / 2 sin ɑ = sin 60° [Standard value of ratios] ɑ = 60° tan β = 1/√3 tan β = tan 30° [Standard value of ratios] β = 30° So, cos (ɑ - β) = cos (60 - 30) = cos 30° = √3 / 2 Hence, the correct answer is : (A) √3 / 2 |
|