# Functions Index :: P :: Parabola

Module:

Definition:

Parabola(float x, float a, bool "up_part", float "xc", float "yc")

Description:

Returns the y-value of `x` so that the point (`x`,y) lies on a parabola parallel to x axis, with edge
located at distance `a` from its focus and its center located at (`xc`,`yc`).

If `xc` or `yc` are not provided they default to zero.

`up_part` determines whether the point will be on the upper or lower part of the curve.
If `up_part` is true or omitted it will on the upper part
(ie >= `yc`), else on the lower (ie < `yc`).

Notes and conditions on arguments relations:

**1]** If `x` >= `xc` the function returns the y-value that corresponds to a parabola opening towards the right x semi-axis; else the y-value that corresponds to a parabola opening towards the left x semi-axis.

**2]** Exchange x,y to get a hyperbola with axis parallel to y axis.

Examples:

TODO in a later version of AVSLib.