Understanding Conic Sections - Parabolas, Circles, Ellipses, and Hyperbolas

Introductionare given by (h +/- a, k).
The following will serve as a brief overview ofOn the other hand, an ellipse centered at (h, k) is
conic sections or in other words, the functionsgiven by [(x - h)^2 / (b^2)] + [(y - k)^2 / (a^2)]
and graphs associated with the parabola, the= 1 when the major axis is vertical. Here, the foci
circle, the ellipse, and the hyperbola. Initially, itare given by (h, k +/- c) and the vertices are
should be noted that these functions are namedgiven by (h, k+/- a).
conic sections since they represent the variousNote that in both types of standard equations for
ways in which a plane can intersect with a pair ofthe ellipse, a > b > 0. Also, c^2 = a^2 - b^2. It is
cones.important to note that 2a always represents the
The Parabolalength of the major axis and 2b always
The first conic section usually studied is therepresents the length of the minor axis.
parabola. The equation of a parabola with aThe Hyperbola
vertex at (h, k) and a vertical axis of symmetryThe hyperbola is probably the most difficult conic
is defined as (x - h)^2 = 4p(y - k). Note that if psection to draw and understand. By memorizing
is positive, the parabola opens upward and if p isthe following equations and practicing by sketching
negative, it opens downward. For this type ofgraphs, one can master even the most difficult
parabola, the focus is centered at the point (h, khyperbola problem.
+ p) and the directrix is a line found at y = k - p.To start, the standard equation of a hyperbola
On the other hand, the equation of a parabolawith center (h, k) and a horizontal transverse axis
with a vertex at (h, k) and a horizontal axis ofis given by [(x - h)^2/a^2] - [(y - k)^2/b^2] = 1.
symmetry is defined as (y - k)^2 = 4p(x - h).Note that the terms of this equation are
Note that if p is positive, the parabola opens toseparated by a minus sign instead of a plus sign
the right and if p is negative, it opens to the left.with the ellipse. Here, the foci are given by the
For this type of parabola, the focus is centered atpoints (h +/- c, k), thevertices are given by the
the point (h + p, k) and the directrix is a linepoints (h +/- a, k) and the asymptotes are
found at x = h - p.represented by y = +/- (b/a)(x - h) +k.
The CircleNext, the standard equation of a hyperbola with
The next conic section to be analyzed is the circle.center (h, k) and a vertical transverse axis is
The equation of a circle of radius r centered atgiven by [(y- k)^2/a^2] - [(x - h)^2/b^2] = 1.
the point (h, k) is given by (x - h)^2 + (y - k)^2Note that the terms of this equation are
= r^2.separated by a minus sign instead of a plus sign
The Ellipsewith the ellipse. Here, the foci are given by the
The standard equation of an ellipse centered at (h,points (h, k +/- c), the vertices are given by the
k) is given by [(x - h)^2/a^2] + [(y - k)^2/b^2]points (h, k +/- a) and the asymptotes are
= 1 when the major axis is horizontal. In this case,represented by y = +/- (a/b)(x - h) + k.
the foci are given by (h +/- c, k) and the vertices