`y=tanx+2cot(5x-π/4)`
$ĐK:\begin{cases}cosx≠0\\sin(5x-\dfrac{π}{4})≠0\end{cases}$
$⇔\begin{cases}x≠\dfrac{π}{2}+kπ\\5x-\dfrac{π}{4}≠kπ\end{cases}$ `(k∈Z)`
$⇔\begin{cases}x≠\dfrac{π}{2}+kπ\\x≠\dfrac{π}{20}+\dfrac{kπ}{5}\end{cases}$ `(k∈Z)`
`TXĐ: D=R`\`{π/2+kπ;π/{20}+{kπ}/5|k∈Z}`