The functions that use different formulas on different parts of their domains are called "piecewise-defined functions".
الإنجليزية - الإنجليزية
تعريف piecewise function في الإنجليزية الإنجليزية القاموس.
In mathematics, a piecewise-defined function f(x) of a real variable x is a function whose definition is given differently on disjoint subsets of its domain
In mathematics, a piecewise-defined function f(x) of a real variable x is a function whose definition is given differently on disjoint subsets of its domain