ExamBro
ExamBro
JEE Mains · Maths · STD 11 - 10.2 parabola,ellipse,hyperbola

If the length of the latus rectum of the ellipse \(x^{2}+\) \(4 y^{2}+2 x+8 y-\lambda=0\) is \(4\) , and \(l\) is the length of its major axis, then \(\lambda+l\) is equal to\(......\)

  1. A \(72\)
  2. B \(73\)
  3. C \(74\)
  4. D \(75\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(75\)

Step-by-step Solution

Detailed explanation

\(\lambda+\ell=75\) \(x^{2}+4 y^{2}+2 x+8 y-\lambda=0\) \(\frac{(x+1)^{2}}{\lambda+5}+\frac{(y+1)^{2}}{\lambda+5}=1\) \(\because \frac{2 b^{2}}{a}=4\) \(\frac{2(\lambda+5)}{4}=4(\sqrt{\lambda+5})\) \(\lambda=59\) \(\lambda \neq-5\) \(l=2 a=2 \sqrt{\lambda+5}=2 \sqrt{65}=16\)…
Same subject
Explore more questions on app