Step 1:
\The radical function
We know that domain is all possible values of
.
We must note that we cannot have a negative value under the square root sign.
\Set the expression under the square root sign greater than or equal to 0.
\\
Solve the inequality 
\
Step 2:
\ 
Solve the related equation

and 
and 
and
Solutions of the equation
are
.
Step 3:
\The solutions are separate the number line into three intervals.
\Now test sample values in each interval to determine whether values in the interval satisfy the inequality.
\Test interval
- value Inequality Conclusion
True
\
False
True
Note that the original inequality contains a “ ≥ ” symbol, We include it into set of solutions at
Solutions of the inequality
is
or
.
Domain of
is
Solution:
\Domain set is
.