Geometry Derivative Show that the normals to the curve $y=4x^2$ from points the same distance on either side of the y-axis intersect on the y-axis.
My attempt, I differentiated so it becomes $8x$, but I don't understand the question. Can anyone explain it to me ? Thanks in advance: 

The normals or tangents to any continuous/smooth curve having an axis of symmetry $A$ at oppositely situated points (mirrored about $A$) must necessarily meet on $A$.
