Let's consider the following cases:

### A) Parabola with origin vertex, right concavity and horizontal symmetry axis

Like the straight line **d** have equation and in the parable we have:

;

P (x, y);

d

_{Federal Police}= d_{Pd}(definition);

We then get the equation of the parable:

y |

### B) Parabola with origin vertex, left concavity and horizontal symmetry axis

Under these conditions, the parable equation is:

y^{2} = -2px |

### C) parabola with vertex in origin, upward concavity and axis of vertical symmetry

x^{2}= 2py |

### D) parabola with vertex in origin, downward concavity and axis of vertical symmetry

x^{2}= - 2py |