Question

If a line makes angle 90°, 60° and 30° with the positive direction of X, Y and Z axes respectively, find its direction cosines

Answer 1

Let the direction cosines of the line be l, m, n.

∴ l = cos 90°, m = cos 60°, n = cos 30°

∴ l = 0, m = `1/2`, n = `sqrt(3)/2`