$\begin{array}{l}
y = \sqrt {x - m + 1} + \frac{{2x}}{{\sqrt { - x + 2m} }}\\
DK:\left\{ \begin{array}{l}
x - m + 1 \ge 0\\
- x + 2m > 0
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
x \ge m - 1\\
x < 2m
\end{array} \right.\\
De\,hs\,xac\,dinh\,tren\,tap\,hop\,D \ne \emptyset \,thi\,m - 1 < 2m \Leftrightarrow m > - 1\\
Khi\,do\,TXD\,D = \left[ {m - 1;2m} \right)\\
Hs\,xac\,dinh\,tren\,\left( { - 1;3} \right) \Leftrightarrow \left( { - 1;3} \right) \subset \left[ {m - 1;2m} \right)\\
\Leftrightarrow m - 1 \le - 1 < 3 \le 2m \Leftrightarrow \left\{ \begin{array}{l}
m - 1 \le - 1\\
2m \ge 3
\end{array} \right. \Leftrightarrow \left\{ \begin{array}{l}
m \le 0\\
m \ge \frac{3}{2}
\end{array} \right.\left( {VN} \right)\\
Vay\,khong\,co\,gia\,tri\,nao\,cua\,m.
\end{array}$
