
William W. answered 02/20/21
Experienced Tutor and Retired Engineer
tan(θ)sec(θ) + 2tan(θ) = 0 Begin by factoring out tan(θ):
tan(θ)[sec(θ) + 2] = 0 Now, using the Zero Product Rule, set each factor equal to zero:
1) tan(θ) = 0 which occurs at θ = 0 and θ = π
2) sec(θ) + 2 = 0
sec(θ) = -2
1/cos(θ) = -2
cos(θ) = -1/2 which occurs at θ = 2π/3 and 4π/3
So the solution then is θ = 0, 2π/3, π, 4π/3