Select the correct answer.

The vertices of an ellipse centered at the origin are [tex]$(-5,0)$[/tex] and [tex]$(5,0)$[/tex], and a point on the ellipse has the coordinates [tex]$(0,2)$[/tex]. What is the equation of the ellipse?

A. [tex]$\frac{x^2}{4^2}+\frac{y^2}{10^2}=1$[/tex]

B. [tex]$\frac{x^2}{2^2}+\frac{y^2}{5^2}=1$[/tex]

C. [tex]$\frac{x^2}{10^2}+\frac{y^2}{4^2}=1$[/tex]

D. [tex]$\frac{x^2}{5^2}+\frac{y^2}{2^2}=1$[/tex]



Answer :

To find the equation of the ellipse, we use the given information about its vertices and a point lying on it.

1. Determine the length of the major axis and the value of [tex]\(a\)[/tex]:
- The vertices of the ellipse are given as [tex]\((-5,0)\)[/tex] and [tex]\((5,0)\)[/tex].
- The distance between the vertices is [tex]\(10\)[/tex], which is the length of the major axis.
- Since the length of the major axis [tex]\(2a = 10\)[/tex], then [tex]\(a = 5\)[/tex].

2. Determine the value of [tex]\(b\)[/tex]:
- A point on the ellipse is given as [tex]\((0,2)\)[/tex], which means when [tex]\(x=0\)[/tex], [tex]\(y\)[/tex] reaches its maximum value, making [tex]\(y = b\)[/tex].
- Therefore, [tex]\(b = 2\)[/tex].

3. Form the equation of the ellipse:
- The standard form of the equation of an ellipse centered at the origin is given by:
[tex]\[ \frac{x^2}{a^2} + \frac{y^2}{b^2} = 1 \][/tex]
- Substituting [tex]\(a = 5\)[/tex] and [tex]\(b = 2\)[/tex]:
[tex]\[ \frac{x^2}{5^2} + \frac{y^2}{2^2} = 1 \][/tex]
- Simplifying:
[tex]\[ \frac{x^2}{25} + \frac{y^2}{4} = 1 \][/tex]

4. Identify the correct choice:
- The correct choice is:
[tex]\[ \frac{x^2}{25} + \frac{y^2}{4} = 1 \][/tex]

Thus, the correct answer is [tex]\(\boxed{\frac{x^2}{5^2} + \frac{y^2}{2^2} = 1}\)[/tex], which corresponds to option D.