If z=eiθz = e^{i\theta}z=eiθ, simplify z+zˉz + \bar{z}z+zˉ.
2cosθ2\cos\theta2cosθ
2isinθ2i\sin\theta2isinθ
eiθ+e−iθe^{i\theta} + e^{-i\theta}eiθ+e−iθ
Both a and c