Question

Find the direction cosines of a line, which is equally inclined to the coordinate axes.

Answer 1

Let the Direction cosines of line be $(l,m,n)$

Since they are equally inclined $l=m=n$

$l^2+m^2+n^2=1l^2+l^2+l^2=13l^2=1l^2=\frac{1}{3}l=\frac{1}{\sqrt{3}}$

So the direction cosines are $(\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}},\frac{1}{\sqrt{3}})$