Definition:Polar Normal

Definition

Let $\CC$ be a curve embedded in a polar plane.

Let $\PP$ be a given point on $\CC$.

Let $\NN$ be the normal to $\CC$ at $\PP$.

Let $\RR$ be the straight line through the pole perpendicular to the radius vector $\mathbf r$ of $\PP$.

Let $\QQ$ be the point of intersection of $\NN$ with $\RR$.

The polar normal of $\PP$ with respect to $\CC$ is the line segment $\PP \QQ$.

Also see

• Definition:Polar Tangent

• Definition:Polar Subnormal
• Definition:Polar Subtangent

• Results about polar normals can be found here.

Sources

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