Consider that the angle between the two vectors a → and b → is θ.
The formula for dot product of vectors a → and b → is,
a → ⋅ b → =| a → || b → |cosθ
Assume | a → |≠0 and | b → |≠0.
It is given that,
a → ⋅ b → ≥0 | a → || b → |cosθ≥0 cosθ≥ 0 | a → || b → | cosθ≥0
It is known that, cosθ≥0when 0≤θ≤ π 2 .
Thus, option (B) is correct.
Choose the correct answer If θ is the angle between two vectors a and b, then a.b≥0 only when a) 0<θ<π2 b) 0≤θ<π2 c) 0<θ<π d) 0≤θ≤π