MY CART (5)

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

ITEM
DETAILS
MRP
DISCOUNT
FINAL PRICE
Total Price: Rs.

There are no items in this cart.
Continue Shopping
Menu
Grade: 12
        

Find locus of the point moving such that sum of their distances from(3,0) and(-3,0) is less than 9 units.


Plz explain me the normal method as well as the other one in which we take PA+PB=2a and AB=2ae

10 years ago

Answers : (1)

jitender lakhanpal
62 Points
							

Dear karhik,

 the locus will be all the points INSIDE the ellipse as the definition of ellipse says that it is the locus all the points whose sum of distances from the fixed points (focii) is constant and that is equal to 2 a where coordinates of focii are (ae,0) and (-ae,0) so if the distance is less than 9 

2a = 9    a=9/2

ae = 3    e = 2/3 

b2 = a2 (1 - e2 )

b2 = 45/4     a2 = 81/4

ellipse is x2 /(81/4)  +  y2 /(45/4) = 1

alternate method   let the point be (h,k)    use distance formula {(h-3)2 + (k-0)2}1/2 + {(h+3)+ (k-0)2}1/2 = 9

(h-3)+ (k-0)2}1/2  = 9 - {(h+3)+ (k-0)2}1/2

now square it  twice you will get the locus of the points and after getting the final equation we get the equation

 

We are all IITians and here to help you in your IIT JEE preparation.

Now you can win by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian.

Now you score 5+15 POINTS by uploading your Pic and Downloading the Askiitians Toolbar : Click here to download the toolbar.. 

jitender 

7 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

  • 731 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
Vouchers
To Win!!! Click Here for details