Solution of $\cos(2x) - A\sin(2x) = 0?$ The physics exercises of today's lecture made me face following equation:

$$\cos(2x) - A\sin(2x) = 0$$

I was not able to solve for $x$? Do you know how to proceed?
(Note: A is $\approx -1/7$)

You can rearrange to get
$$\tan(2x)=\frac{1}{A}\,.$$
The general solution is
$$x=\frac{1}{2}\arctan\left(\frac{1}{A}\right)+\frac{n\pi}{2},$$
where $n$ is an integer.
