পরাবৃত্তের ফোকাস এবং দিকাক্ষ

Question: How do we graph quadratics like $y=$ $x^{2}$ $+$ $2x$ $+$ $4?$

Answer: The parabola!

Given a line l and a point p, a parabola is the set of points x such that the length of xp equals the distance from x to l. Point p is called the focus and the line is called the directrix.