Determine the value of the expression cos(180∘−θ)+cos(180∘+θ)\cos(180^\circ - \theta) + \cos(180^\circ + \theta)cos(180∘−θ)+cos(180∘+θ).
2cos(θ)2\cos(\theta)2cos(θ)
−2cos(θ)-2\cos(\theta)−2cos(θ)
000
2sin(θ)2\sin(\theta)2sin(θ)