Definition:One-Parameter Family of Curves

Definition
Consider the implicit function $f \left({x, y, c}\right) = 0$ in the $\left({x, y}\right)$-plane where $c$ is a constant.

For each value of $c$, we have that $f \left({x, y, c}\right) = 0$ defines a relation between $x$ and $y$ which can be graphed in the cartesian coordinate plane.

Thus, each value of $c$ defines a particular curve.

The complete set of all these curves for each value of $c$ is called a one-parameter family of curves.