Find the condition for the line y=mx+cy = mx + cy=mx+c to be tangent to the parabola y2=4axy^2 = 4axy2=4ax.
c=a/mc = a/mc=a/m
c=m/ac = m/ac=m/a
c=a/m2c = a/m^2c=a/m2
c2=a/mc^2 = a/mc2=a/m