Question

Write an equation for the parabola with a vertex at the origin and focus (2,0)

Answer 1

Check the picture below.

so is horizontal parabola, meaning the squared variable is the "y".  It has a "p" distance of 2 units, let's notice that it opens to the right, meanign "p" is positive.

$\bf \textit{parabola vertex form with focus point distance} \\\\ \begin{array}{llll} \stackrel{\textit{we'll use this one}}{4p(x- h)=(y- k)^2} \\\\ 4p(y- k)=(x- h)^2 \end{array} \qquad \begin{array}{llll} vertex\ ( h, k)\\\\ p=\textit{distance from vertex to }\\ \qquad \textit{ focus or directrix} \end{array} \\\\[-0.35em] ~\dotfill\\\\ \begin{cases} h=0\\ k=0\\ p=2 \end{cases}\implies 4(2)(x-0)=(y-0)^2\implies 8x=y^2\implies x=\cfrac{1}{8}y^2$