The value of $\sin 10^\circ \sin 30^\circ \sin 50^\circ \sin 70^\circ$ is

If $A = \sin 45^{\circ} + \cos 45^{\circ}$ and $B = \sin 44^{\circ} + \cos 44^{\circ}$,then

If $\tan \theta \cdot \cos 60^{\circ} = \frac{\sqrt{3}}{2}$,then the value of $\sin (\theta - 15^{\circ})$ is

The value of $\sqrt{3} \operatorname{cosec} 20^{\circ} - \sec 20^{\circ} = $

Let $f(x) = Ax^3 - Bx - \tan x \cdot \text{sgn}(x)$ be an even function for all $x \in \mathbb{R} - \left\{ (2n + 1) \frac{\pi}{2}, n \in \mathbb{Z} \right\}$, where $A = \sin^2 \alpha - \sin \alpha + \frac{1}{4}$ and $B = \tan^2 \alpha + \frac{2}{\sqrt{3}} \tan \alpha + \frac{1}{3}$. Then the number of values of $\alpha$ in $\left[ -\frac{3\pi}{2}, 2\pi \right]$ is (where $\text{sgn}(x)$ denotes the signum function of $x$).

If $\tan \alpha$ equals the integral solution of the inequality $4x^2 - 16x + 15 < 0$ and $\cos \beta$ equals the slope of the bisector of the first quadrant,then $\sin(\alpha + \beta)\sin(\alpha - \beta)$ is equal to