Inverse Trigono...

$$\sec\ h^{-1}\left(\dfrac{1}{5}\right)$$=

If $$\cot \dfrac {2x}{3}+\tan \dfrac {x}{3}=\csc \dfrac {x}{3}$$ then value of $$\tan^{-1(\tan k)}$$ equals

If $$f ( x ) = \sqrt { \sec ^ { - 1 } \left( \frac { 2 - | x | } { 4 } \right) } ,$$ then the domain of $$f ( x )$$ is ______________.

The value of $${ sin }^{ -1 }(sin12)+{ cos }^{ -1 }(cos12)$$ is equal to :

$$\displaystyle \sum _{ r=1 }^{ n }{ { tan }^{ -1 } } \left(\dfrac { { 2 }^{ r-1 } }{ 1+{ 2 }^{ 2r-1 } } \right)$$ is equal to :

If $$3{\tan ^{ - 1}}\left( {\frac{1}{{2 + \sqrt 3 }}} \right) - {\tan ^{ - 1}}\frac{1}{x} = {\tan ^{ - 1}}\frac{1}{3}$$ then $$x = $$

For $$0<x<1$$ the value of $$\cos^{-1}x+\cos^{-1}(-x)=?$$

The value of $$\sin\ h(\cos\ h^{-1}x)$$ is 

The value of $$\displaystyle \sum_{r=0}^{\infty}{ tan}^{1}\left(\dfrac{1}{1+r+{r}^{2}}\right)$$  is equal to

The simplified form of $${ cos }^{ -1 }\left( \frac { 3 }{ 5 } { cos }x+\frac { 4 }{ 5 } { sin }x \right) $$ is :