Gujarati
10-2. Parabola, Ellipse, Hyperbola
easy

If the eccentricity of an ellipse be $5/8$ and the distance between its foci be $10$, then its latus rectum is

A

$39/4$

B

$12$

C

$15$

D

$37/2$

Solution

(a) $a = \frac{{10}}{{\frac{{2.5}}{8}}} = 8$, $b = 8\sqrt {1 – \frac{{25}}{{64}}} = 8\frac{{\sqrt {39} }}{8}$ = $\sqrt {39} $

Latus rectum$ = \frac{{2{b^2}}}{a} = \frac{{2 \times 39}}{8} = \frac{{39}}{4}$.

Standard 11
Mathematics

Similar Questions

Start a Free Trial Now

Confusing about what to choose? Our team will schedule a demo shortly.