AP EAMCET2008MathematicsEllipse
For an ellipse with eccentricity 1 2 the centre is at the origin. If one directrix is x=4 , then the equation of the ellipse is
Options
- A3 x^2+4 y^2=1
- B3 x^2+4 y^2=12
- C4 x^2+3 y^2=1
- D4 x^2+3 y^2=12
Correct answer
B. 3 x^2+4 y^2=12
Step-by-step solution
Given that, e= 1 2 and a e =4 array lrl & a 1 / 2 =4 a=2 Using & b^2=a^2 (1-e^2 ) & b^2=4 (1- 1 4 )=3 array Equation of ellipse is aligned x^2 4 + y^2 3 & =1 3 x^2+4 y^2 & =12 aligned