Liam D. answered 09/17/23
Math Tutor and Student at Columbia University
There are no domain restrictions on an absolute value, meaning that you can plug in any real number for the x-value and still produce a real number as an output. Knowing this, the domain of f(x) is all real numbers,
which can be written in interval notation as D: (-∞, ∞).
In interval notation, the "(" and ")" indicate non-inclusivity and the "[" and "]" indicate inclusivity. It is standard convention to use the parentheses for -∞ and ∞.
Now for the Range:
Remember, an absolute value causes negative numbers to become positive. Knowing this, any y-values less than 0 will now become positive and, therefore, greater than 0. This means that y ≥ 0 or that R: [0, ∞).
Hope this helped :)