Find the Nulls of the N-element array in which elements are separated by λ/4 and phase difference is 0?

\(θ_n=cos^{-1}⁡(\left[±\frac{2n}{N}\right])\)

\(θ_n=cos^{-1}⁡(\left[±\frac{4n}{N}\right])\)

\(θ_n=cos^{-1}⁡(\left[±\frac{2n}{N}\right])\)

\(θ_n=sin⁡(\left[±\frac{4n}{N}\right])\)

\(θ_n=sin^{-1}⁡(\left[±\frac{4n}{N}\right])\)

Find the Nulls of the N-element array in which elements are separated

1.	Find the Nulls of the N-element array in which elements are separated by λ/4 and phase difference is 0?
A.	\(θ_n=cos^{-1}⁡(\left[±\frac{4n}{N}\right])\)
B.	\(θ_n=cos^{-1}⁡(\left[±\frac{2n}{N}\right])\)
C.	\(θ_n=sin⁡(\left[±\frac{4n}{N}\right])\)
D.	\(θ_n=sin^{-1}⁡(\left[±\frac{4n}{N}\right])\)
Answer» B. \(θ_n=cos^{-1}⁡(\left[±\frac{2n}{N}\right])\)