Properties of Parabolas .

A parabola is a plane curve, which is mirror-symmetrical, and is approximately U-shaped when oriented

Vertical

vertex ( h, k)

Focus will be (h.k+1/4a)

y = a( x – h) 2 + k

Directrix (k-1/4a)

Axis of symmetry X=h

Horizontal

vertex ( h, k)

Focus (h+1/4a,k)

Axis of symmetry Y=k

Directrix (h-1/4a)

x = a( y – k) 2 + h.

DONE BY;Abeer Aba Alkhail 12C

The different point between the vertex and focus must be the same with the directrix.

The Obj: is to learn what is parabola and the different two type vertical and horizontal in a graph and equation.

If the a was -ve the both sides if the sketch will be down ward.

If the a was -ve both side of the sketch will be to the right.