What is the condition for a straight line y = mx + c to be normal to a parabola y ^ 2 = 4ax ?
If normal at the point -LSB- math -RSB- -LRB- am ^ 2,-2am -RRB- -LSB- / math -RSB- of the parabola -LSB- math -RSB- y ^ 2 = 4ax -LSB- / math -RSB- , subtends a right angle at the vertex , what is the value of -LSB- math -RSB- m -LSB- / math -RSB- ?