Useful information about parabolas:
Vertical axis Horizontal axis
Standard Form: (x-h)²=4p(y-k) (y-k)²=4p(x-h)
Eccentricity: e=1 e=1
Length of latus rectum: l=|4p| l=|4p|
Directrix: y=k-p x=h-p
Vertex: (h,k) (h,k)
Focus: (h,k+p) (h+p,k)
Opening direction: p<0 down, p>0 up p<0 left, p>0 right
Parametric Form: x′=2pt+h x′=2pt²+h
y′=2pt²+k y′=2pt+k
See also: