Tính

a) $\sin x =$$\frac{1}{3}$, $90 < x < 180. Tính A =$$\frac{\tan x + 3cotx + 1}{\tan x + cotx}$.
​b)$\sin$$\alpha$ = $\frac{2}{3}$$. Tính A =$$\frac{cot\alpha - \tan \alpha }{cot\alpha + \tan \alpha }$
c)$\tan$$\alpha = \sqrt{2}$.$Tính B =$$\frac{\sin \alpha - \cos \alpha }{{\sin }^3\alpha + 3 {\cos }^3\alpha + 2\sin \alpha }$
d) $\tan \alpha = 3. Tính C = \frac{{\sin }^2 \alpha -5{\cos }^2\alpha }{2{\sin }^2\alpha +3\sin \alpha .\cos \alpha +{\cos }^2\alpha }$