A line makes the same angle $\theta $, with each of the $x$ and $z$ axis. If the angle $\beta \,$, which it makes with y-axis, is such that $\,{\sin ^2}\beta = 3{\sin ^2}\theta ,$ then ${\cos ^2}\theta $ equals :

Question

A line makes the same angle $\theta $, with each of the $x$ and $z$ axis.

If the angle $\beta \,$, which it makes with y-axis, is such that $\,{\sin ^2}\beta = 3{\sin ^2}\theta ,$ then ${\cos ^2}\theta $ equals :

${2 \over 5}$