If $1 + \sin x + {\sin ^2}x + .....$ to $\infty = 4 + 2\sqrt 3 ,\,0 < x < \pi ,$ then
$x = \frac{\pi }{6}$
$x = \frac{\pi }{3}$
$x = \frac{\pi }{3}$ or $\frac{\pi }{6}$
$x = \frac{\pi }{3}$ or $\frac{{2\pi }}{3}$
Let $S$ be the sum of all solutions (in radians) of the equation $\sin ^{4} \theta+\cos ^{4} \theta-\sin \theta \cos \theta=0$ in $[0,4 \pi]$ Then $\frac{8 \mathrm{~S}}{\pi}$ is equal to ...... .
If $\sin x=\frac{3}{5}, \cos y=-\frac{12}{13},$ where $x$ and $y$ both lie in second quadrant, find the value of $\sin (x+y)$.
If $tanA + cotA = 4$, then $tan^4A + cot^4A$ is equal to
The equation $\sin x + \cos x = 2$has
If $0 \le x \le \pi $ and ${81^{{{\sin }^2}x}} + {81^{{{\cos }^2}x}} = 30$, then $x =$