# Increasing Function

## Increasing Function

If [a, b] is an interval in the domain of a function f, we say that the function f is increasing in the interval [a, b] if and only if for all elements x1 and x2 of [a, b], if x1 < x2, then f(x1) ≤ f(x2).

### Example

Consider the function defined by f(x) = 3x + 2.

• If $$x_{1} = 0$$, then f(0) = 2.
• If $$x_{2} = 2$$, then f(2) = 8.
• Therefore: f(0) ≤ f(2).
• And the function defined by f(x) = 3x + 2 is increasing.