Question

class 10 th lesson trigonometry

Answer 1

cos²Ф/(cot²Ф - cos²Ф) = 3
3(cot²Ф - cos²Ф)/cos²Ф = 1
3(1/sin²Ф- 1) = 1 
3(1 - sin²Ф)/sin²Ф = 1
3cos²Ф/sin²Ф = 1
cot²Ф = 1/3 
cotФ = 1/√3
Ф = cot⁻¹(1/√3)
Ф = 60° ANSWER