ĐKXĐ: ...
\(\Leftrightarrow tan\left(3x+\frac{\pi}{2}\right)=\frac{1}{cot\left(5x+1\right)}=tan\left(5x+1\right)\)
\(\Leftrightarrow5x+1=3x+\frac{\pi}{2}+k\pi\)
\(\Leftrightarrow2x=\frac{\pi}{2}-1+k\pi\)
\(\Rightarrow x=\frac{\pi}{4}-\frac{1}{2}+\frac{k\pi}{2}\)