What is the equation of the ellipse whose vertices are ($$\pm$$ 5, 0) and foci are at ($$\pm$$ 4, 0) ?

If the angle between the lines joining the end points of minor axis of the ellipse $${{{x^2}} \over {{a^2}}} + {{{y^2}} \over {{b^2}}} = 1$$ with one of the its foci is $${\pi \over 2}$$, then what is the eccentricity of the ellipse?

The sum of the focal distances of a point on an ellipse is constant and equal to

The equation $$2{x^2} - 3{y^2} - 6 = 0$$ represents