Let $S=\{x \in R: \cos (x)+\cos (\sqrt{2} x)<2\}$, then
$S=\emptyset$
$S$ is a non-empty finite set
$S$ is an infinite proper subset of $R-\{0\}$
$S=R-\{0\}$
One root of the equation $\cos x - x + \frac{1}{2} = 0$ lies in the interval
The general value of $\theta $satisfying the equation $2{\sin ^2}\theta - 3\sin \theta - 2 = 0$ is
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 $\cos 2\theta + 3\cos \theta = 0$, then the general value of $\theta $ is
Find the general solution of the equation $\cos 3 x+\cos x-\cos 2 x=0$