Equation of Conic in Cartesian Coordinates is Quadratic

Theorem

Let $\CC$ be a conic section.

Then $\CC$ can be expressed by an quadratic equation in $2$ variables.

Proof

This theorem requires a proof. In particular: Follows apparently from Conic Section is Curve of Second Order. Sommerville is not rigorous about defining his terms. You can help $\mathsf{Pr} \infty \mathsf{fWiki}$ by crafting such a proof. To discuss this page in more detail, feel free to use the talk page. When this work has been completed, you may remove this instance of {{ProofWanted}} from the code. If you would welcome a second opinion as to whether your work is correct, add a call to {{Proofread}} the page.

Sources

• 1933: D.M.Y. Sommerville: Analytical Conics (3rd ed.) ... (previous) ... (next): Chapter $\text {IV}$. The Ellipse: $1 \text a$. Focal properties