Conic Sections
Conic sections: an introduction from space | Maths, Physics and Apps
De radi 2
$$ x^2+y^2=4 $$
De radi $a=2$ i $b=3$
$$ \frac{x^2}{4}+\frac{y^2}{9}=1 $$
$$ y=4x^2+3 $$