Final answer:
A piecewise function is used when a function is defined by different rules or formulas for different parts of its domain.
Step-by-step explanation:
A piecewise function is used when a function is defined by different rules or formulas for different parts of its domain. It is typically indicated by using different equations or expressions for different intervals or conditions of x. For example, consider the piecewise function:
f(x) = 2x for x ≤ 0
f(x) = x^2 for x > 0
In this case, the function has different rules for x ≤ 0 and x > 0. When x is zero or less, the function is defined as 2x, and when x is greater than zero, the function is defined as x^2.