NTA Abhyas JEE Main2020MathematicsTrigonometric Ratios & IdentitiesPractice
In a triangle A B C , if sin ⁡ A cos ⁡ B = 1 4 and 3 tan ⁡ A = tan ⁡ B , then cot 2 ⁡ A is equal to
Options
- A2
- B3
- C4
- D5
Correct answer
B. 3
Step-by-step solution
3 sin A cos B = sin B cos A ⇒ cos A sin B = 3 4 ⇒ sin A + B = 1 ⇒ C = π 2 , B = π 2 - A 3 tan A = tan π 2 - A = cot A ⇒ cot 2 A = 3