Parabolas #2

Parabolas are U shaped graphs. They have a focus, which is right above the vertex and that distance is called c and is (h,k+c) . The vertex is the center of the parabola such is (h,k). The directrix is y=k-c and is the line below the vertex. The parts described are for a graph that has a c>0, or positive. If the c<0, or negative, then the parts are reversed. The basic equation for a positive parabola is (x-h)^2=4c(y-k) and the basic equation for a negative parabola is (y-k)^2=4c(x-h).