The statement pattern $(p \vee q) \rightarrow \sim r$ is logically equivalent to

In $\triangle ABC$, with usual notations, if $\cos A = \dfrac{1}{2}, a = 3, \angle B = \dfrac{\pi^c}{6}$, then the values of $b$ and $c$ are.....

If $A = \dfrac{1}{2}\begin{bmatrix} -1 & -\sqrt{3} \\ \sqrt{3} & -1 \end{bmatrix}$ then $A^{-1} - A^2$ is not

If $A = \begin{bmatrix} 2i & i^3 \\ i^2 & 1 \end{bmatrix}$, then $A^{-1}$ is equal to