Question
Question: If the segment intercepted by the parabola y<sup>2</sup> = 4ax with the line lx + my + n = 0 subtend...
If the segment intercepted by the parabola y2 = 4ax with the line lx + my + n = 0 subtends a right angle at the vertex,
then-
A
4al + n = 0
B
4al + 4am + n = 0
C
4am + n = 0
D
al + n = 0
Answer
4al + n = 0
Explanation
Solution
y2 = 4ax (1)
y2 = 4ax 
ny2 = – 4alx2 – 4amxy
4alx2 + ny2 + 4a mxy = 0
coeff. of x2 + coeff. of y2 = 0
4al + n = 0