Question

7cos^2 thita+3sin^2 thita =4 then secthita =_____

Answer 1

let theta = Ф
7cos²Ф + 3sin²Ф = 4
4cos²Ф + 3(cos²Ф+sin²Ф) = 4                 (cos²Ф+sin²Ф = 1)
4cos²Ф + 3 = 4
4cos²Ф = 1
cos²Ф = 1/4
sec²Ф = 4
secФ = 2 or -2