The domain is the set of all numbers that can be substituted for x
such that the result will be a defined value.

The dominator must not be 0, so we must not have x-3 = 0 or x = 3
So the domain must leave out 3

There also must be no negative numbers under the square root.
There is no concern about the (x+2)² because even if x+2 were negative,
its square would be positive.  So we only have to require that x-1 be ≧ 0,
which gives x ≧ 1, so the domain on a number line is

-------------------------⚫=======⚪===========>
-5  -4  -3  -2  -1   0   1   2   3   4   5   6 

and in interval notation is



Edwin