Parabola in the plane

### 26.11.3 Parabola in the plane

For parabolas in space, see Section 27.9.4.

The parabola command draws parabolas and other conic sections. parabola can take parameters in two different ways.

- parabola can take one argument: eqn, a second degree equation in the variables x and y (or an expression which will be set to zero).
- parabola(eqn) returns and draws the conic section given by the equation eqn.
- Alternatively, parabola can take two arguments: F,V, two points, or
  - A=(a,b), a point.
  - c, a real number.
- parabola(F,V) returns and draws the parabola with focus F and vertex V.
- parabola(A,c) returns and draws the parabola y=b+c(x−a)2.

#### Examples

parabola(x^2-y-1)

parabola(0,i)

parabola(-i,1)

parabola(-i,i,1/2)