## Tried my best

1)in a triangle ABC angleB and angle c is $2\theta$ BD bisects angle B
0< $\theta$<45 satisfies
$2\cos\theta \sin\theta(1+2\cos\theta) = \sin4\theta + \sin\theta$
the angleA of triangle ABC is

2) if $0<\alpha<\frac{\pi}{2}$ and $0<\beta<\frac{\pi}{2}$ and $\cos\alpha\cos\beta\cos\(\alpha +\beta) = \frac{-1}{8}$

then $\alpha\beta = ??$