Question

What are the direction cosines of a line, which makes equal angles with the co-ordinates axes?

Answer 1

Let α be the angle made by line with coordinate axes.

 => Direction cosines of line are cos α , cos α , cos α

Hence, the direction cosines, of the line equally inclined to the coordinate axes are

[Note : If l, m, n are direction cosines of line, then l² + m² + n² =1]​