What is the modulus of eiθ+eiϕe^{i\theta} + e^{i\phi}eiθ+eiϕ?
2cos(θ−ϕ2)2\cos(\frac{\theta-\phi}{2})2cos(2θ−ϕ)
2∣cos(θ−ϕ2)∣2|\cos(\frac{\theta-\phi}{2})|2∣cos(2θ−ϕ)∣
2sin(θ−ϕ2)2\sin(\frac{\theta-\phi}{2})2sin(2θ−ϕ)
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