Questions in inv-trig

Select	Question
	${{\sec }^{-1}}[\sec (-{{30}^{o}})]=$
	${{\tan }^{-1}}\left[ \frac{\cos x}{1+\sin x} \right]=$
	${{\tan }^{-1}}\frac{1}{\sqrt{{{x}^{2}}-1}}=$
	The principal value of ${{\sin }^{-1}}\left( -\frac{1}{2} \right)$is
	${{\sec }^{2}}({{\tan }^{-1}}2)+\text{cose}{{\text{c}}^{2}}({{\cot }^{-1}}3)=$
	${{\sin }^{-1}}\left[ x\sqrt{1-x}-\sqrt{x}\sqrt{1-{{x}^{2}}} \right]=$
	If ${{\tan }^{-1}}\frac{1-x}{1+x}=\frac{1}{2}{{\tan }^{-1}}x$, then $x =$
	${{\cos }^{-1}}\left( \cos \frac{7\pi }{6} \right)=$
	The value of $\sin {{\cot }^{-1}}\tan {{\cos }^{-1}}x$ is equal to
	${{\sin }^{-1}}\frac{\sqrt{x}}{\sqrt{x+a}}$ is equal to