BITSAT2015MathematicsEllipseActual
The eccentricity of an ellipse, with its centre at the origin, is 1 / 2 . If one of the directrices is x =4 then the equation of the ellipse is:
Options
- A4 x²+3 y²=1
- B3 x²+4 y²=12
- C4 x²+3 y²=12
- D3 x²+4 y²=1
Correct answer
B. 3 x²+4 y²=12
Step-by-step solution
e = 1 2 . Directrix , x = a e =4 a =4 1 2 =2 b =2 1- 1 4 = 3 Equation of ellispe is x² 4 + y² 3 =1 3 x²+4 y²=12