1. **Problem Statement:** Find the centre, vertices, minor axis points, and foci of the ellipse given by the equation
$$4x^2 + 9y^2 - 16x + 18y - 11 = 0$$
2. **Rewrite the equation by grouping and completing the square:**
$$4x^2 - 16x + 9y^2 + 18y = 11$$
Group terms:
$$4(x^2 - 4x) + 9(y^2 + 2y) = 11$$
Complete the square inside each parenthesis:
For $x^2 - 4x$, add and subtract $4$:
$$x^2 - 4x + 4 - 4 = (x - 2)^2 - 4$$
For $y^2 + 2y$, add and subtract $1$:
$$y^2 + 2y + 1 - 1 = (y + 1)^2 - 1$$
3. **Substitute back:**
$$4((x - 2)^2 - 4) + 9((y + 1)^2 - 1) = 11$$
Expand:
$$4(x - 2)^2 - 16 + 9(y + 1)^2 - 9 = 11$$
Simplify constants:
$$4(x - 2)^2 + 9(y + 1)^2 = 11 + 16 + 9 = 36$$
4. **Divide both sides by 36 to get standard form:**
$$\frac{4(x - 2)^2}{36} + \frac{9(y + 1)^2}{36} = 1$$
Simplify fractions:
$$\frac{(x - 2)^2}{9} + \frac{(y + 1)^2}{4} = 1$$
5. **Identify ellipse parameters:**
- Centre: $(2, -1)$
- $a^2 = 9$, so $a = 3$ (major axis radius)
- $b^2 = 4$, so $b = 2$ (minor axis radius)
Since $a^2 > b^2$, major axis is along the $x$-axis.
6. **Vertices:**
Along $x$-axis from centre:
$$ (2 \pm 3, -1) = (-1, -1) \text{ and } (5, -1) $$
7. **Minor axis points:**
Along $y$-axis from centre:
$$ (2, -1 \pm 2) = (2, -3) \text{ and } (2, 1) $$
8. **Foci:**
Calculate $c$ where $c^2 = a^2 - b^2 = 9 - 4 = 5$, so $c = \sqrt{5}$.
Foci along major axis ($x$-axis):
$$ (2 \pm \sqrt{5}, -1) $$
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**Summary for part (a):**
- Centre: $(2, -1)$
- Vertices: $(-1, -1)$ and $(5, -1)$
- Minor axis points: $(2, -3)$ and $(2, 1)$
- Foci: $(2 - \sqrt{5}, -1)$ and $(2 + \sqrt{5}, -1)$
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1. **Problem Statement:** Find the centre, vertices, minor axis points, and foci of the ellipse given by the equation
$$x^2 + 2y^2 - 10x + 8y + 29 = 0$$
2. **Group and complete the square:**
Group $x$ and $y$ terms:
$$x^2 - 10x + 2(y^2 + 4y) = -29$$
Complete the square for $x$:
$$x^2 - 10x + 25 - 25 = (x - 5)^2 - 25$$
Complete the square for $y$ inside the parentheses:
$$y^2 + 4y + 4 - 4 = (y + 2)^2 - 4$$
3. **Substitute back:**
$$ (x - 5)^2 - 25 + 2((y + 2)^2 - 4) = -29 $$
Expand:
$$ (x - 5)^2 - 25 + 2(y + 2)^2 - 8 = -29 $$
Simplify constants:
$$ (x - 5)^2 + 2(y + 2)^2 = -29 + 25 + 8 = 4 $$
4. **Divide both sides by 4:**
$$ \frac{(x - 5)^2}{4} + \frac{2(y + 2)^2}{4} = 1 $$
Simplify:
$$ \frac{(x - 5)^2}{4} + \frac{(y + 2)^2}{2} = 1 $$
5. **Identify ellipse parameters:**
- Centre: $(5, -2)$
- $a^2 = 4$, $a = 2$
- $b^2 = 2$, $b = \sqrt{2}$
Since $a^2 > b^2$, major axis is along the $x$-axis.
6. **Vertices:**
Along $x$-axis from centre:
$$ (5 \pm 2, -2) = (3, -2) \text{ and } (7, -2) $$
7. **Minor axis points:**
Along $y$-axis from centre:
$$ (5, -2 \pm \sqrt{2}) $$
8. **Foci:**
Calculate $c$ where $c^2 = a^2 - b^2 = 4 - 2 = 2$, so $c = \sqrt{2}$.
Foci along major axis ($x$-axis):
$$ (5 \pm \sqrt{2}, -2) $$
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**Summary for part (b):**
- Centre: $(5, -2)$
- Vertices: $(3, -2)$ and $(7, -2)$
- Minor axis points: $(5, -2 + \sqrt{2})$ and $(5, -2 - \sqrt{2})$
- Foci: $(5 - \sqrt{2}, -2)$ and $(5 + \sqrt{2}, -2)$
Ellipse Properties Dfe3Db
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