Analyzing Polar Equations for Conic Sections

Key Questions

  • There are two basic kinds of parabola(as it is convenient for me to say)

    Type 1:
    The parabola lying on, or parallel to the #x-#axis

    This parabola is of the form #(y-y_v)^2=4a(x-x_v)#

    Where,
    - focus is #(a+x_v,y_v)#
    - directrix is the line #x=x_v-a#
    - Vertex is #(x_v,y_v)#

    Type 2:
    The parabola lying on, or parallel to the #y-#axis

    This parabola is of the form #(x-x_v)^2=4a(y-y_v)#

    Where,
    - focus is #(x_v,a+y_v)#
    - directrix is the line #y=y_v-a#
    - Vertex is #(x_v,y_v)#

  • Answer:

    The directrix is the vertical line #x=(a^2)/c#.

    Explanation:

    For a hyperbola #(x-h)^2/a^2-(y-k)^2/b^2=1#,

    where #a^2+b^2=c^2#,

    the directrix is the line #x=a^2/c#.

    mathworld.wolfram.com

Questions