Bullet-nose curve explained

In mathematics, a bullet-nose curve is a unicursal quartic curve with three inflection points, given by the equation

a2y2-b2x2=x2y2

The bullet curve has three double points in the real projective plane, at and, and, and and, and is therefore a unicursal (rational) curve of genus zero.

If

f(z)=

infty
\sum
n=0

{2n\choosen}z2n+1=z+2z3+6z5+20z7+ …

then

y=f\left(

x
2a

\right)\pm2b

are the two branches of the bullet curve at the origin.

References