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1)

The equation  of the circle passing through the foci of the ellipse 

x216+y29=1  and having centre at (0,3) is 


A) x2+y26y7=0

B) x2+y26y+7=0

C) x2+y26y5=0

D) x2+y26y+5=0

Answer:

Option B

Explanation:

Given  equation of ellipse is  x216+y29=1  

442021340_m2.JPG

 Here, a=4,b=3,   e=191674

   Foci is (±,0)= (±4×74,0)

=(±7,0)

   Radius of the circle,

           r=(ae)2+b2=7+9=16=4

 Now, equation of circle is 

                      (x0)2+(y3)2=16

     x2+y26y7=0