Ellipse Properties
1. Problem: Analyze the ellipses in Figures 1 and 2 and find the center, vertices, co-vertices, foci, lengths of axes, and equations for each.
**Figure 1:**
1. Center: The ellipse is centered at the origin, so the center is $\boxed{(0,0)}$.
2. Vertices: The ellipse crosses the x-axis at $\pm7$, so the vertices are $\boxed{(7,0)}$ and $\boxed{(-7,0)}$.
3. Co-vertices: The ellipse crosses the y-axis at $\pm5$, so the co-vertices are $\boxed{(0,5)}$ and $\boxed{(0,-5)}$.
4. Foci: For an ellipse centered at origin with major axis along x-axis, the foci are at $\pm c$ where
$$c=\sqrt{a^2 - b^2}=\sqrt{7^2 - 5^2}=\sqrt{49-25}=\sqrt{24}=2\sqrt{6}$$
so foci are at $\boxed{(2\sqrt{6},0)}$ and $\boxed{(-2\sqrt{6},0)}$.
5. Lengths:
- Major axis length = $2a=2\times7=14$
- Minor axis length = $2b=2\times5=10$
6. Standard equation:
Since major axis is along x-axis,
$$\frac{x^2}{7^2}+\frac{y^2}{5^2}=1 \implies \frac{x^2}{49}+\frac{y^2}{25}=1$$
General equation by multiplying both sides by 1225:
$$25x^2 + 49 y^2 = 1225$$
**Figure 2:**
1. Center: Again, centered at origin $\boxed{(0,0)}$.
2. Vertices: Vertices are along the y-axis at approximately $\pm5$, so vertices are $\boxed{(0,5)}$ and $\boxed{(0,-5)}$.
3. Co-vertices: Co-vertices along x-axis approximately at $\pm3$, so co-vertices are $\boxed{(3,0)}$ and $\boxed{(-3,0)}$.
4. Foci: For ellipse with major axis vertical,
$$c=\sqrt{a^2-b^2}=\sqrt{5^2 - 3^2}=\sqrt{25 - 9} = \sqrt{16} = 4$$
Foci are located at $\boxed{(0,4)}$ and $\boxed{(0,-4)}$.
5. Lengths:
- Major axis length = $2a=2\times5=10$
- Minor axis length = $2b=2\times3=6$
6. Standard equation:
Major axis along y-axis,
$$\frac{x^2}{3^2} + \frac{y^2}{5^2} =1 \implies \frac{x^2}{9} + \frac{y^2}{25} =1$$
General equation by multiplying by 225:
$$25x^2 + 9y^2 = 225$$
Final answers summarized:
- Figure 1:
- Center: $(0,0)$
- Vertices: $(\pm7,0)$
- Co-vertices: $(0,\pm5)$
- Foci: $(\pm 2\sqrt{6},0)$
- Major axis length: 14
- Minor axis length: 10
- Standard Eq: $\frac{x^2}{49}+\frac{y^2}{25}=1$
- General Eq: $25x^2 + 49 y^2 = 1225$
- Figure 2:
- Center: $(0,0)$
- Vertices: $(0,\pm5)$
- Co-vertices: $(\pm3,0)$
- Foci: $(0,\pm4)$
- Major axis length: 10
- Minor axis length: 6
- Standard Eq: $\frac{x^2}{9} + \frac{y^2}{25} =1$
- General Eq: $25x^2 + 9 y^2 = 225$