Q278
If 4sin2θ = 3(1 + cosθ), 0° < θ < 90°, then what is the value of (2tanθ + 4sinθ - secθ)?
A.
Answer
B.
C.
D.
Answer: Option A
Solution
Answer: Option A
Solution:
4sin2θ = 3(1 + cosθ)4(1 - cos2θ) = 3 + 3cosθ
4 - 4cos2θ = 3 + 3cosθ
4cos2θ + 3cosθ - 1 = 0
4cos2θ + 4cosθ - cosθ - 1 = 0
4cosθ(cosθ + 1) - 1(cosθ + 1) = 0
(4cosθ -1)(cosθ + 1) = 0
4cosθ - 1 = 0
cosθ =

Then, 2tanθ + 4tanθ - secθ