Written by the Fiveable Content Team โข Last updated September 2025
Written by the Fiveable Content Team โข Last updated September 2025
Definition
An increasing function is a function where the value of the output increases as the input increases. Mathematically, for any two values $x_1$ and $x_2$ such that $x_1 < x_2$, the function $f(x)$ satisfies $f(x_1) \leq f(x_2)$.
5 Must Know Facts For Your Next Test
In an increasing function, if $x_1 < x_2$ then $f(x_1) \leq f(x_2)$ holds true.
If the inequality is strict, i.e., $f(x_1) < f(x_2)$ when $x_1 < x_2$, then the function is called strictly increasing.
The slope of the graph of an increasing linear function is always positive.
In calculus terms, if the derivative of a function $f'(x) > 0$ for all $x$ in its domain, then it is an increasing function.
An increasing function may have flat regions where the slope is zero but does not decrease at any point.
Review Questions
Related terms
Decreasing Function: A decreasing function is one where as the input increases, the output decreases. Mathematically, for any two values $x_1$ and $x_2$ such that $x_1 < x_2$, then $f(x_1) \geq f(x_2)$.