## Tried my best

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

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

then $\displaystyle \alpha\beta = ??$