ellipse
(noun)
The conic section formed by the plane being at an angle to the base of the cone.
(noun)
One of the conic sections.
Examples of ellipse in the following topics:
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Ellipses as Conic Sections
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Parts of an Ellipse
- Ellipses are one of the types of conic sections.
- The standard form for the equation of the ellipse is:
- if the ellipse is oriented vertically.
- For a vertical ellipse, the association is reversed.
- An eccentricity of $1$ is a parabola, not an ellipse.
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Ellipses
- And the resulting shape will be an ellipse.
- How often do ellipses come up in real life?
- The sun is at one focus of the ellipse (not at the center).
- If a>b, the ellipse is horizontal.
- If a, the the ellipse is vertical.
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Introduction to Ellipses
- An ellipse is one of the shapes called conic sections, which is formed by the intersection of a plane with a right circular cone.
- The general equation of an ellipse centered at $\left(h,k\right)$ is:
- which is exactly the equation of a horizontal ellipse centered at the origin.
- An ellipse is a conic section, formed by the intersection of a plane with a right circular cone.
- Connect the equation for an ellipse to the equation for a circle with stretching factors
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What Are Conic Sections?
- The three types of conic sections are the hyperbola, the parabola, and the ellipse.
- In the case of an ellipse, there are two foci, and two directrices.
- In the next figure, a typical ellipse is graphed as it appears on the coordinate plane.
- They could follow ellipses, parabolas, or hyperbolas, depending on their properties.
- The sum of the distances from any point on the ellipse to the foci is constant.
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Types of Conic Sections
- The definition of an ellipse includes being parallel to the base of the cone as well, so all circles are a special case of the ellipse.
- Ellipses have these features:
- A major axis, which is the longest width across the ellipse
- A minor axis, which is the shortest width across the ellipse
- Ellipses can have a range of eccentricity values: $0 \leq e < 1$.
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Eccentricity
- Recall that hyperbolas and non-circular ellipses have two foci and two associated directrices, while parabolas have one focus and one directrix.
- For an ellipse, the eccentricity is less than $1$.
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Applications of Circles and Ellipses
- Circles and ellipses are encountered in everyday life, and knowing how to solve their equations is useful in many situations.
- Ellipses are less common.
- One example is the orbits of planets, but you should be able to find the area of a circle or an ellipse, or the circumference of a circle, based on information given to you in a problem.
- Circles and ellipses are examples of conic sections, which are curves formed by the intersection of a plane with a cone.
- This almost looks like an ellipse in standard form, doesn't it?
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Nonlinear Systems of Equations and Problem-Solving
- The four types of conic section are the hyperbola, the parabola, the ellipse, and the circle, though the circle can be considered to be a special case of the ellipse.
- Conics with eccentricity less than $1$ are ellipses, conics with eccentricity equal to $1$ are parabolas, and conics with eccentricity greater than $1$ are hyperbolas.
- In the focus-directrix definition of a conic, the circle is a limiting case of the ellipse with an eccentricity of $0$.
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Standard Equations of Hyperbolas
- Similar to a parabola, a hyperbola is an open curve, meaning that it continues indefinitely to infinity, rather than closing on itself as an ellipse does.
- A conjugate axis of length 2b, corresponding to the minor axis of an ellipse, is sometimes drawn on the non-transverse principal axis; its endpoints ±b lie on the minor axis at the height of the asymptotes over/under the hyperbola's vertices.