1. The problem statement, all variables and given/known data This problem is from the Australian HSC mathematics extension 2 exam. Q6ciii) It states: Find the focus, S, of the parabola [tex]y^2=r^2+c^2-2cx[/tex] where r and c are constants. 3. The attempt at a solution I couldn't figure out how to convert this into the parabola focus form (which, from the top of my head) might be [tex](x-x_o)^2=4a(y-y_o)[/tex] for the focus [tex]S(x_o,y_o+a)[/tex] How is this done?