If α is a root of x4=1 which negative principle argument, then the principle argument of △(α)=∣∣ ∣ ∣ ∣∣11αnαn+1αn+31αn+11αn0∣∣ ∣ ∣ ∣∣ is
Which of the following statements are correct?
1 . if sin θ = sin α ⇒ θ = nπ + (−1)nα where α ∈ [ - π2 , π2] n ∈ I
2 . if cos θ = cos α ⇒ 2nπ±α where α ∈ [0,π] n ∈ I
3 . if tan θ = tan α ⇒ θ = nπ + α where α ∈ (- π2 , π2 ) n ∈ I