Find the Domain and Range of \(f(x)=-|x|\)
Question:
Find the domain and range of the real valued function:
$$
f(x)=-|x|
$$
Solution
Domain
The modulus function is defined for every real number.
Hence, the domain is: $$ \mathbb{R} $$
Range
Since $$ |x|\ge0 $$
Therefore, $$ -|x|\le0 $$
Maximum value occurs at $$ x=0 $$
$$ f(0)=-|0|=0 $$
As \(|x|\) increases, \(-|x|\) decreases without bound.
Hence, the range is: $$ (-\infty,0] $$