. If the chord
y = mx + c subtends a right angle at the vertex of the parabola y2 = 4ax, then the value of c is
A. – 4am
B. 4am
C. –2am
D. 2am
Best Answer
Ans: A
Sol: 
Coefficient of x2 + Coefficient of y2 = 0 Þ c = –4am.
Related questions
y = mx + c subtends a right angle at the vertex of the parabola y2 = 4ax, then the value of c is
A. – 4am
B. 4am
C. –2am
D. 2am
Ans: A
Sol:
Coefficient of x2 + Coefficient of y2 = 0 Þ c = –4am.
