Illumination of a parabola with table calculations
This parabola analysis includes a table with 3D calculations for relative intensity
Delta R is the width of the segment between points (ex between V and W)
delta area is the area of the ring segment (ex. ring segment V to W is pi*[(VW+UV)^2 - (UV)^2])
rel. intensity compares all areas to the ring segment UV (1)