Writing Polar Equations for Conic Sections

Key Questions

  • General form of the conic equation

    #Ax^2+Bxy+Cy^2+Dx+Ey+F=0#

    The coefficients #A# and #C# are need to identify the conic sections without having to complete the square.

    #A# and #C# cannot be #0# when making this determination.

    Parabola#->A*C=0#

    Circle#->A=C#

    Ellipse#->A*C>0 and A!=C#

    Hyperbola#->A*C<0#

  • Standard form equations for the hyperbola.

    #x^2/a^2-y^2/b^2=1#

    The foci are located on the #x#-axis also called the transverse .

    #y^2/a^2-x^2/b^2=1#

    The foci are located on the #y#-axis also called the transverse .

  • Standard form for the equation of a parabola is the same as standard for for a quadratic function:
    #y =ax^2+bx+c#

    Or
    #f(x) = ax^2+bx+c#.

    For graphing, many prefer the vertex form

    #y=a (x-h)^2 +k#

  • Answer:

    A conic section is a section (or slice) through a cone.

    Explanation:

    Depending on the angle of the slice, you can create different conic sections,

    Conic Sections
    (from en.wikipedia.org)

    If the slice is parallel to the base of the cone, you get a circle.

    If the slice is at an angle to the base of the cone, you get an ellipse.

    If the slice is parallel to the side of the cone, you get a parabola.

    If the slice intersects both halves of the cone, you get a hyperbola.

    There are equations for each of these conic sections, but we will not include them here.

Questions