# If θ is the angle between two vectors $$\overrightarrow{a} and \overrightarrow{b}$$ when is $$\overrightarrow{a} ⋅ \overrightarrow{b} ≥ 0$$

If θ is the angle between two vectors $$\overrightarrow{a} and \overrightarrow{b}$$ , then $$\overrightarrow{a} ⋅ \overrightarrow{b} ≥ 0$$ only when

(A) 0 < θ < π/2
(B) 0 ≤ θ ≤ π/2
(C) 0 < θ < π
(D) 0 ≤ θ ≤ π

A)    is the answer because a  .  b  =  ab cosø   which is positive in 1st quadrant