 Also, a function can be said to be strictly monotonic on a range of values, and thus have an inverse on that range of value.For example, if y=g(x) is strictly monotonic on the range [a,b], then it has an inverse x=h(y) on the range [g(a), g(b)], but we cannot say the entire range of the function has an inverse.Note, some textbooks mistakenly state that an inverse exists for a monotonic function, when they really mean that an inverse exists for a strictly monotonic function.