7 boys and 5 girls are to be seated around a circular table such that no two girls sit together is?
Let $y=f(x)$ represent a parabola with focus $\left(-\frac{1}{2}, 0\right)$ and directrix $y=-\frac{1}{2}$ Then $S=\left\{x \in R : \tan ^{-1}(\sqrt{f(x)})+\sin ^{-1}(\sqrt{f(x)+1})=\frac{\pi}{2}\right\}$ :
Let \( \mathbf{A} = 2\hat{i} + \hat{j} - 2\hat{k} \) and \( \mathbf{B} = \hat{i} + \hat{j} \). If \( \mathbf{C} \) is a vector such that \( |\mathbf{C} - \mathbf{A}| = 3 \) and the angle between \( \mathbf{A} \times \mathbf{B} \) and \( \mathbf{C} \) is \( 30^\circ \), then \( [(\mathbf{A} \times \mathbf{B}) \times \mathbf{C}] = 3 \), the value of \( \mathbf{A} \cdot \mathbf{C} \) is equal to: