JEE Main 202431 JanuaryEvening Shift
- Exam
- JEE Main
- Year
- 2024
- Date
- 31 January
- Shift
- Evening Shift
- Subject
- Mathematics
- Chapter
- Ellipse
JEE Main 2024 · 31 January · Evening Shift · Mathematics · Ellipse
Let P be a parabola with vertex (2, 3) and directrix 2x + y = 6 ....
Let be a parabola with vertex and directrix . Let an ellipse of eccentricity pass through the focus of the parabola . Then the square of the length of the latus rectum of , is
Options
- A
- B
- C
- D
Correct answer
D.
Step-by-step solution
Let be the foot of perpendicular from vertex to directrix of parabola,
Now, finding we get,
Eccentricity of ellipse is given as .
Now, finding using eccentricity formula we get,
So, equation of ellipse will be,
{as \left(\dfrac{12}{5}, \dfrac{16}{5}\right)}</p><p>⇒ \dfrac{144}{25{a}^{2}} + \dfrac{512}{25{a}^{2}} = 1⇒ \dfrac{656}{25{a}^{2}} = 1⇒ {a}^{2} = \dfrac{656}{25}⇒ {b}^{2} = \dfrac{328}{25}L = \dfrac{2{b}^{2}}{a}⇒ L = \dfrac{2 \times \dfrac{328}{25}}{\dfrac{\sqrt{656}}{5}}⇒ L = \dfrac{\sqrt{656}}{5}⇒ {L}^{2} = \dfrac{656}{25}