Find the value of ∑k=0ncos(kθ)\sum_{k=0}^{n} \cos(k\theta)∑k=0ncos(kθ) where n=2n=2n=2 and θ=π3\theta = \frac{\pi}{3}θ=3π.
000
111
0.50.50.5
1.51.51.5