section_path: Definition/Parametric equation
section_name: Parametric equation
paragraph_text: Parametric equation
  
  Parametric equations are also used to specify lines, particularly in those in three dimensions or more because in more than two dimensions lines cannot be described by a single linear equation.
  
  In three dimensions lines are frequently described by parametric equations: x = x 0 + a t y = y 0 + b t z = z 0 + c t {\displaystyle {\begin{aligned}x&=x_{0}+at\\y&=y_{0}+bt\\z&=z_{0}+ct\end{aligned}}} where:
  
  Parametric equations for lines in higher dimensions are similar in that they are based on the specification of one point on the line and a direction vector.