noun
inverse function
Mathematical term for a function that reverses another function.
f(x) = 2x の逆関数は f⁻¹(x) = x/2 です。
The inverse function of f(x) = 2x is f⁻¹(x) = x/2.
指数関数の逆関数は対数関数です。
The inverse function of an exponential function is a logarithmic function.