Find the condition for the line y=mx+cy = mx + cy=mx+c to be a normal to the parabola y2=4axy^2 = 4axy2=4ax.
c=−2am−am3c = -2am - am^3c=−2am−am3
c=2am+am3c = 2am + am^3c=2am+am3
c=amc = \frac{a}{m}c=ma
c=−am3c = -\frac{a}{m^3}c=−m3a