n ఒక ధన పూర్ణాంకమైతే. \({\left( {1 + i\sqrt 3 } \right)^n} + {\left( {1 - i\sqrt 3 } \right)^n} = \)
1
\({2^{n - 1}}\cos \frac{{n\pi }}{3}\)
2
\({2^n}\cos \frac{{n\pi }}{3}\)
3
\({2^{n + 1}}\cos \frac{{n\pi }}{3}\)
4
\({2^{2n}}\cos \frac{{n\pi }}{3}\)