Task B-3.3. Solve the equation:

$$
\cos 2012 x - \cos 2010 x = 0
$$
## Second Solution.

$$
\begin{aligned}
& \cos 2012 x - \cos 2010 x = 0 \\
& -2 \sin \frac{2012 x + 2010 x}{2} \sin \frac{2012 x - 2010 x}{2} = 0 \\
& \sin 2011 x \sin x = 0
\end{aligned}
$$

From this, $\sin x = 0$ or $\sin 2011 x = 0$.

From the first equation, $x = k \pi, k \in \mathbb{Z}$,

and from the second, $2011 x = k \pi, k \in \mathbb{Z},$ i.e., $x = \frac{k \pi}{2011}, k \in \mathbb{Z}$.

Note: Credit the student if they did not write $x = k \pi$.