Question

rotate the pic for question.
please solve this trigonometric equation question​

Answer 1

Answer:

The correct answer is option A

Step-by-step explanation:

cos2θ + 3cosθ =0

=> [2cos^2(θ) - 1] + 3cosθ =0

=>2cos^2(θ) + 3cosθ - 1 = 0

Let cosθ = t

Using quadratic formula, t = option A

Therefore, cosθ = option A

Hope you find this useful