VGLA conics Flashcards
4 conics
circle, ellipse, hyperbola, parabola
special case conics
degenerate conics
parabola definition
the set of all points in a plane that are equidistant from a given fixed point and a fixed line in the plane
Standard Equation of Parabolar theorem
The standard equation of a parabolar with focus at the point F(0,p) and directrix y = -p with p>0 is given by
x² = 4py
A parabola is symmetric with respect to…
the y axis
when p is small for x² = 4py
the parabola is narrow
When p is large for x² = 4py
the parabola is wide
transformation formula for rotation
x' = xcosθ + ysinθ y' = ycosθ - xsinθ
transformation formula for translation
x' = x-p y' = y-q
The standard equation for a parabola with the directrix in the opposite direction
y² = 4px
equation of a parabola with focus at the point F(√2/2p,√2/2p) and directrix y = x-√2p with p>0 is given by
(x-y)² = 4p√2(x+y)
How else can the equation of a parabola be written as
ax² + bx + c =y
the vertex and axis of a parabola with equation ax² + bx + c =y
P(-b/2a, c- b²/4a)
x = -b/2a
tangent to a parabola
yy’ = 2p(x+x’)
reflective property of a parabola
The tangent and the normal at a point of a parabola are the bissectors of the angles defined by the line PF, with F the focus, and the line through P parallel to the axis of the parabola