Step 1: Condition for \(\sqrt{2-x}\).
For square roots to be real,
\[
2-x\geq 0
\]
So,
\[
x\leq 2
\]
Step 2: Condition for \(\sqrt{1+x}\).
For square root to be real,
\[
1+x\geq 0
\]
So,
\[
x\geq -1
\]
Step 3: Condition for denominator \(\sqrt{x+3}\).
Since \(\sqrt{x+3}\) is in the denominator, we need:
\[
x+3\gt 0
\]
So,
\[
x\gt -3
\]
Step 4: Find common domain.
Combining all conditions:
\[
x\leq 2,\quad x\geq -1,\quad x\gt -3
\]
The common interval is:
\[
[-1,2]
\]
Step 5: Final conclusion.
Hence, the domain is
\[
\boxed{[-1,2]}
\]