BITSAT2011MathematicsEllipseActual
The equation of the ellipse with focus at (( 5,0) ) and (x= 36 5 ) as one directrix is
Options
- A( x^2 36 + y^2 25 =1 )
- B( x^2 36 + y^2 11 =1 )
- C( x^2 25 + y^2 11 =1 )
- DNone of these
Correct answer
B. ( x^2 36 + y^2 11 =1 )
Step-by-step solution
We have ae (=5 ) [Since focus is (( ae , 0) )] and ( a e = 36 5 [ . ) since directrix is ( . x = a e ] ) On solving we get ( a =6 ) ( and e = 5 6 b ^2= a ^2 (1- e ^2 )=36 (1- 25 36 )=11 ) Thus, the required equation of the ellipse is ( x^2 36 + y^2 11 =1 )