The dot product of two vectors

The dot product of two vectors vanishes when vectors are orthogonal and has maximum value when vectors are parallel to each other. Explain.

We know that A • B = AB cos θ, when vectors are orthogonal θ = 90°. So, A.B = AB cos90° = 0, when vectors are parallel then θ = 0°. So, A • B = AB cos 0° = AB (maximum)