Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: Rs.

There are no items in this cart.
Continue Shopping
Grade: 11
        Prove that locus of a point whose chord of contact with respect to parabola passes through focus is directrix
2 years ago

Answers : (1)

Partha Math Expert - askIITians
askIITians Faculty
25 Points
							Let the parabola be y2= 4ax and any ponit on the locus be (h,k). Then the chord of contact of (h,k) is given by:
T = 0 or 2yk – 4a(x+h) = 0
Since it passes through the focus (a,0).
Plugging it in: a + h = 0
Thus, x = -a is the locus, which is also the directrix.

Here, T = 0 means doing the following subsitutions:
x2→ xh
y2→ yk
x → (x + h)/2
y → (y+k)/2
xy → (xk + yh)/2
in the general equation of any conic, which is y2– 4ax = 0 in this case.
2 years ago
Think You Can Provide A Better Answer ?
Answer & Earn Cool Goodies

Course Features

  • 731 Video Lectures
  • Revision Notes
  • Previous Year Papers
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Test paper with Video Solution

Course Features

  • 53 Video Lectures
  • Revision Notes
  • Test paper with Video Solution
  • Mind Map
  • Study Planner
  • NCERT Solutions
  • Discussion Forum
  • Previous Year Exam Questions

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!! Click Here for details