3. The solution set of the inequality $\sin x \cdot|\sin x|>\cos x \cdot|\cos x|$ is . $\qquad$
3. $\left\{x \left\lvert\, \frac{\pi}{4}+2 k \pi\cos x \cdot|\cos x|$
$$
\Leftrightarrow \sin x>\cos x \text {. }
$$

Therefore, the solution set is
$$
\left\{x \left\lvert\, \frac{\pi}{4}+2 k \pi<x<\frac{5 \pi}{4}+2 k \pi(k \in \mathbf{Z})\right.\right\} .
$$