Question

If $\cos 3x=0$ and $x$ is acute, the value of $\sin x$ is $\frac{1}{m}$. Then, $m$ is:

Answer 1

$cos3x=0$
$cos3x=cos90$
$3x=90$
$x={30}^{\circ }$
Now, $sinx=sin30=\frac{1}{2}$