Previous
Serie XVII
Next

# Serie XVII, Nr 2a

## The seven types of plane curves of order three principal.

**Mathematical description**

This models represents a sphere with three of the seven principal types of
plane curves of order three on it.
The equations from the four plane curves are from the inside til the outside starting with the blue ellipse-like figure:

y^{2} = 1/4 (x+12)(x+5)(x+2)
y^{2} = 1/x 9(x+1)^{2}(x+6)
y^{2} = 1/4 (x+9/2)^{2}(x+1)
y^{2} =-1/x (x+9/2})^{3}

This plane curves are projected on the sphere with projective geometry.
**Title model and translation**

Die sieben Haupttypen der ebenen Curven 3. Ordnung.

The seven types of plane curves of order three principal.

**Text on Sticker and translation**

I. 4 typen Kugelprojection d.ebenen curven 3. ord.

I. Four types spherical projection even curves of order three.

**Designer**

Dollinger under the supervision of Dr. Brill

Tübingen in 1886

**Company**

Martin Schilling in Halle a.S.

**Original price**

Mark 12 (two pieces)

**Dimension**

10 cm

**Material**

Plaster

**Literature**

Schilling, M., Catalog mathematischer Modelle für den höheren
mathematischen Unterricht, Leipzig: Verlag von Martin Schilling, 1911