Definition:Orthogonal (Analytic Geometry)

Definition

Orthogonal Curves

Let $C_1$ and $C_2$ be curves that intersect at a point $P$.

$C_1$ and $C_2$ are orthogonal at $P$ if and only if the tangent line to $C_1$ at $P$ is at right angles to the tangent line to $C_2$ at $P$.

Also known as

Two objects that are orthogonal are often seen described as perpendicular.

However, the latter usually used where those objects are straight lines or planes.

Also see

• Results about orthogonality in the context of geometry can be found here.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): orthogonal
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): orthogonal