If a line y=mx+cy = mx + cy=mx+c is tangent to the parabola y2=4axy^2 = 4axy2=4ax, what is the condition on ccc?
c=a/mc = a/mc=a/m
c=m/ac = m/ac=m/a
c=a2/mc = a^2/mc=a2/m
c=m2/ac = m^2/ac=m2/a