Given:
The functions are:
(1)

(2)

(3)

To find:
The domain of given functions.
Solution:
Domain is the set of input and x -values.
Value under the square root must be positive because if the number under square root is negative, then it is a complex or imaginary number.
(1)

The function is defined if


The function is defined for all real values of x which are less than or equal to 1.
Therefore, the domain of the function is (-∞,1].
(2)

It is a linear function and linear function is defined for all real values of x.
Therefore, the domain of the function is (-∞,∞).
(3)

It can be written as


It is defined if



This function defined for all real values of x from -4 to 4.
Therefore, the domain of the function is [-4,4].