Let \(\vec{a}\) and \(\vec{b}\) be two unit vectors and θ is the angle between them. Then \(\vec{a}+\vec{b}\) is a unit vector if
A. θ = \(\frac{\pi}{4}\)
B. θ = \(\frac{\pi}{3}\)
C. θ = \(\frac{\pi}{2}\)
D. θ = \(\frac{2 \pi}{3}\)
Answer:D
Let \(\vec{a}\) and \(\vec{b}\) be two unit vectors and θ is the angle between them. Then \(\vec{a}+\vec{b}\) is a unit vector if
A. θ = \(\frac{\pi}{4}\) B. θ = \(\frac{\pi}{3}\) C. θ = \(\frac{\pi}{2}\) D. θ = \(\frac{2 \pi}{3}\)