Q.

If (1,–2) is the focus and +y-2=0 is the directix of the  ellipse 17x2-2xy+17y2-32x+76y+86=0 then its  eccentricity is

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!
An Intiative by Sri Chaitanya

a

1/4

b

1/3

c

1/5

d

1/2

answer is C.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Given focus =(1, -2) and equation of directrix is x+y-2=0 

Now let P(x, y) be any point on ellipse then equation of ellipse is 

(x-1)2+(y+2)2=e2(x+y-2)22     

 2x2+1-2x+y2+4+4y=e2x2+y2+4+2xy-4y-4x 

 x2(2-e2)-2e2xy+(4e2-4)x+(2-e2)y2+(8+4e2)y+10-4e2=0   -(1)

Given equation of ellipse is 

17x2-2xy+17y2-32x+76y+86=0   -(2)

 since (1)&(2) represents same line then

2-e217=2e22=4e2-4-32  2-e2=17e2  18e2=2  e2=19  e=13

Watch 3-min video & get full concept clarity

tricks from toppers of Infinity Learn

score_test_img

Get Expert Academic Guidance – Connect with a Counselor Today!

whats app icon