The signum function, denoted as \( \text{sgn}(x) \), is a piecewise function defined as follows:
\[ \text{sgn}(x) = \begin{cases} -1 & \text{if } x < 0 \\ 0 & \text{if } x = 0 \\ 1 & \text{if } x > 0 \end{cases} \]
The range of the signum function is the set of possible output values it can take. In this case, the range is \(\{-1, 0, 1\}\) because these are the only values that the function can output based on its definition for negative, zero, and positive values of \(x\), respectively.