Obtain the scalar product of unit vectors in Cartesian co-ordinate system.
Find the angle between two vectors $\vec A = 2\hat i + \hat j - \hat k$ and $\vec B = \hat i - \hat k$ ....... $^o$
The angle between two vectors $ - 2\hat i + 3\hat j + \hat k$ and $\hat i + 2\hat j - 4\hat k$ is ....... $^o$
Obtain the scalar product of two mutually perpendicular vectors.