Write the direction cosines of a line parallel to z-axis.

Explanation

A line parallel to `z`-axis, makes an angle of `90^{circ}, 90^{circ}` and `0^{circ}` with the `x, y` and `z` axes, respectively.


Thus, the direction cosines are given by


``
`I=cos 90^{circ}=0`


`m=cos 90^{circ}=0`


`n=cos 0=1`


``
Therefore, direction cosines of a line parallel to the `z`-axis are `0,0,1`.