The solution of $tan\,\, 2\theta\,\, tan\theta = 1$ is
$\frac{\pi }{3}$
$(6n \pm 1)\frac{\pi }{6}$
$(4n \pm 1)\frac{\pi }{6}$
$(2n \pm 1)\frac{\pi }{6}$
The general solution of the trigonometric equation $tan\, x + tan \,2x + tan\, 3x = tan \,x · tan\, 2x · tan \,3x$ is
General solution of $eq^n\, 2tan\theta \, -\, cot\theta =\, -1$ is
The number of solutions that the equation $sin5\theta cos3\theta = sin9\theta cos7\theta $ has in $\left[ {0,\frac{\pi }{4}} \right]$ is
The number of values of $x$ in the interval $\left(\frac{\pi}{4}, \frac{7 \pi}{4}\right)$ for which $14 \operatorname{cosec}^{2} x-2 \sin ^{2} x=21$ $-4 \cos ^{2} x$ holds, is
The solution of $\frac{1}{2} +cosx + cos2x + cos3x + cos4x = 0$ is