Evaluate: $\cos^{-1}\sqrt{1-x} + \sin^{-1}\sqrt{1-x}$

Write $\cot ^{-1}\left(\frac{1}{\sqrt{x^{2}-1}}\right), x>1$ in the simplest form.

$\coth^{-1}(2) + \operatorname{cosech}^{-1}(-2\sqrt{2}) = $

The number of solutions of $|\sin^{-1}x| = |x|$ is

If $f(x) = \frac{\sqrt{\operatorname{Cos}^{-1} x}}{\sqrt{2(1-x)}}$ for $x < 1$,then $\lim_{x \rightarrow 1^{-}} f(x) =$

Let $a, b$ and $c$ be the lengths of the sides of a triangle with its opposite angles $A, B$ and $C$ respectively. If $a=3, b=4$ and $A=\sin^{-1}\left(\frac{3}{4}\right)$,then the angle $B$ is (in $^{\circ}$)