Subtangent
= Subtangent
{title2=$CE$}
For a point $B$ of a <curve>, let its ordinate meet the chosen coordinate axis at $C$, and its <tangent> meet that axis at $E$. The segment $CE$ is the <subtangent>. It depends on the chosen axis. For the standard <parabola>, $CE=2CD$, where $D$ is its <vertex of a parabola>.