If the line lx + my + n = 0 touches the parabola y2 = 4ax, then
(a) In = am
(b) In2 = am2
(c) l2n = am2
(d) In = am2
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
Correct option (D) ln = am2
Explanation :
Suppose lx + my + n = 0 touches the parabola y2 = 4ax at (at2, 2at). However, ty = x + at2 is the equation of the tangent at (at2, 2at). Therefore
l/1 = m/-t = n/at2
⇒ – m/l = t = -n/ma
⇒ am2 = ln