The equation of an ellipse whose eccentricity is $1/2$ and the vertices are $(4, 0)$ and $(10, 0)$ is
$3{x^2} + 4{y^2} - 42x + 120 = 0$
$3{x^2} + 4{y^2} + 42x + 120 = 0$
$3{x^2} + 4{y^2} + 42x - 120 = 0$
$3{x^2} + 4{y^2} - 42x - 120 = 0$
The equation of the ellipse whose foci are $( \pm 5,\;0)$ and one of its directrix is $5x = 36$, is
If the radius of the largest circle with centre $(2,0)$ inscribed in the ellipse $x^2+4 y^2=36$ is $r$, then $12 r^2$ is equal to
The ellipse $\frac{{{x^2}}}{{{a^2}}} + \frac{{{y^2}}}{{{b^2}}} = 1$ and the straight line $y = mx + c$ intersect in real points only if
If the eccentricity of an ellipse be $1/\sqrt 2 $, then its latus rectum is equal to its