The vertex and focus of a parabola are at a distance of h and k units on positive x–axis from origin. Then equation of parabola is

Let Focus =S, Vertex =V

$$\begin{gathered} Given that \\ \mathrm{OV}=\mathrm{h},\mathrm{OS}=\mathrm{k} \\ \mathrm{Vertex} \mathrm{V}=\left(\mathrm{h},0\right) \\ Dis\tan ce between vertex and focus =\mathrm{a}=\mathrm{k}-\mathrm{h} \\ \mathrm{Now} \mathrm{equation} \mathrm{of} \mathrm{parabola} \mathrm{is} \\ {\mathrm{y}}^2=4\left(\mathrm{k}-\mathrm{h}\right)\left(\mathrm{x}-\mathrm{h}\right) \end{gathered}$$