Q.
If the system of linear equations :
$x + 3y + 7z = 0 $
$-x + 4y + 7z = 0$
$(\sin 3 \theta ) x + (\cos 2 \theta) y + 2z = 0 $
has a non-trivial solution, then the number of values of 6 lying in the interval $[0, \pi ]$, is :
Solution: