Dot or Scalar Product of Vectors
Dot Product of two vectors A and B is defines as product of magnitude of the vectors and cosine of the angle between them.
A•B = |A||B|CosT, Where T is the angle between the vectors A and B.
It is a scalar quantity
Special Cases
(I) If two vectors are perpendicular to each other their dot product is Zero.
(ii) If two vectors A and B are parallel their dot product is |A||B|.
If i, j, k are unit vectorsalong X, Y, Z axis respectively then
i.i = 1
j.j = 1
k.k = 1
i.j = 0
j.k = 0
K.i = 0.
Note : Scalar product is commutative
i.e. A.B = B.A