A parametric equation is a set of equations that express $x$ and $y$ in terms of a parameter $t$.
The limit of a function $f(x)$ as $x$ approaches $a$ is denoted by $\lim_x\to a f(x)$. A parametric equation is a set of equations
Analytic geometry is the study of geometric shapes using algebraic and analytic methods. A parametric equation is a set of equations