Inverse

In math, an *inverse* undoes the effect of an operation or function. For a number, the inverse under addition is its opposite (e.g., the inverse of 5 is −5), and under multiplication it’s its reciprocal (e.g., the inverse of 5 is 1/5). For a function ( f(x) ), the inverse ( f^(x) ) reverses its action so that ( f(f^(x)) = x ).