The vertical component ofvelocity of the airplane will give us the velocity with which the airplane moves away from the Earth.Â
As the aeroplane takes off at angle  with horizontal,Â
 ∴       Â
∴         Â
If  are the magnitudes of rectangular components of velocity vector of magnitude v, then
         Â
Given,
         and   Â
∴        Â
     Â
That is,
        , is the magnitude of other rectangular component of velocity.Â
Determine the direction cosines of a vectorÂ
The vector is given by,
            Â
The X, Y and Z components of the vector are,Â
∴  ,,          Â
So, the resultant of the vector is given by,
    Â
Thus,Â
Direction cosine is,Â