The beginning of learning about functions goes through first degree functions. In this post, we will present some first-degree functions. Among them are constant, linear and related. Constant function The constant function is a plateau, something flat or simply a horizontal line. Below we present the formal definition. Definition (Constant Function): an application $f$ of $\mathbb{R}$ in $\mathbb{R}$ is called a constant function when each element $x \in\mathbb{R}$ always associates the same element $c \in\mathbb{R}$.