Questions in inv-trig

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	If ${{\sin }^{-1}}x+{{\sin }^{-1}}y+{{\sin }^{-1}}z=\frac{\pi }{2}$, then the value of ${{x}^{2}}+{{y}^{2}}+{{z}^{2}}+2xyz$is equal to
	$\sin \left[ \frac{\pi }{2}-{{\sin }^{-1}}\left( -\frac{\sqrt{3}}{2} \right) \right]=$
	$\sin [{{\cot }^{-1}}(\cos {{\tan }^{-1}}x)]$=
	If $\sin ({{\cot }^{-1}}(x+1)=\cos ({{\tan }^{-1}}x)$, then x =
	${{\cos }^{-1}}\frac{4}{5}+{{\tan }^{-1}}\frac{3}{5}=$
	${{\sin }^{-1}}x+{{\sin }^{-1}}\frac{1}{x}+{{\cos }^{-1}}x+{{\cos }^{-1}}\frac{1}{x}=$
	$2{{\tan }^{-1}}\frac{1}{3}+{{\tan }^{-1}}\frac{1}{2}=$
	$\tan \left( {{90}^{o}}-{{\cot }^{-1}}\frac{1}{3} \right)=$
	$\tan \left[ {{\cos }^{-1}}\frac{4}{5}+{{\tan }^{-1}}\frac{2}{3} \right]$=
	${{\tan }^{-1}}1+{{\tan }^{-1}}2+{{\tan }^{-1}}3=$