1.
Let θ∈(0,π2)\theta \in (0, \frac{\pi}{2}). If the system of linear equations
(1+cos⁡2θ)x+sin⁡2θ y+4sin⁡3θ z=0,(1 + \cos^2 \theta) x + \sin^2 \theta \, y + 4 \sin 3\theta \, z = 0,

cos⁡2θ x+(1+sin⁡2θ)y+4sin⁡3θ z=0,\cos^2 \theta \, x + (1 + \sin^2 \theta) y + 4 \sin 3\theta \, z = 0,

cos⁡2θ x+sin⁡2θ y+(1+4sin⁡3θ)z=0\cos^2 \theta \, x + \sin^2 \theta \, y + (1 + 4 \sin 3\theta) z = 0

has a non-trivial solution, then the value of θ\theta is: