Inverse Trigono...

Multiple choice Questions :
If a > b > c ,
$$ \cot^{-1} \left ( \dfrac{1 + ab}{a - b} \right ) + \cot^{-1}\left ( \dfrac{1 + bc}{b - c} \right ) + \cot^{-1} \left ( \dfrac{1 + ac}{c - a} \right ) $$

Multiple choice Questions :
$$ \sin^{-1}\left ( \dfrac{4}{5} \right ) + \cos^{-1}\left ( \dfrac{4}{5} \right )=$$

Multiple choice Questions :
$$ \cos^{-1} \cos \left ( \dfrac{4 \pi}{3} \right ) = $$ 

$$\tan ^{-1}\left ( \dfrac{x}{y} \right ) - \tan^{-1} \dfrac{x - y}{x + y}$$ is equal to

$$2\tan(\tan^{-1}x+\tan^{-1}x^3)$$ is:

If $$\sin^{-1}\left(\dfrac{1}{2}\right)=x$$, then general value $x$$ is:

If $$\tan^{-1}(3x)+\tan^{-1} 2x=\dfrac{\pi}{4}$$, then $$x$$ is:

If $$\tan^{-1}(1)+\cos^{-1}(\dfrac{1}{\sqrt{2}})=\sin^{-1}x$$, then value of $$x$$ is

If $$\cot^{-1}x+\tan^{-1}\dfrac{1}{3}=\dfrac{\pi}{2}$$ then $$x$$ is: