Help!!!! : Complex Root of unity question
Could anyone please help me solve this Cambride Book qs :(Exercise 2.4) question 4
Use DeMoivre's theorem to solve z^5 =1 by grouping the roots in complex conjugate pairs ,show that
z^5 +1 = (z+1)(z^2-2zcos pi/5 +1 ) (z^2-2zcos 3pi/5 +1 )...