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TRANSCRIPT
EllipsesLESSON 10.4
Objective
Define ellipses and parts of an ellipse
Graph ellipses
Find the equation of an ellipse
Ellipses
An ellipse is the set of all points on a plane whose distance from two fixed focal points (foci) add up to
a constant number.
Ellipses
A line drawn through an ellipse containing the foci is
called the major axis. The intersections between the major axis and the ellipse are the vertices 𝑉1 and 𝑉2.
Ellipses
𝑥−ℎ 2
𝑎2+
𝑦−𝑘 2
𝑏2= 1 major axis: ↔
𝑥−ℎ 2
𝑏2+
𝑦−𝑘 2
𝑎2= 1 major axis: ↕
*NOTE: 𝑎 > 𝑏
Ellipses
Identify the center of the ellipse, 𝑎, and 𝑏.
1) 𝑥2
9+
𝑦2
49= 1 2)
𝑥−1 2
25+
𝑦−4 2
9= 1
Ellipses
Identify the center of the ellipse, 𝑎, and 𝑏.
3) 𝑥−1 2
4+
𝑦+2 2
16= 1 4) 𝑥 − 2 2 +
𝑦2
4= 1
Ellipses
The major axis has two points that intersect the
ellipse. These points are vertices. Vertices can be found by adding and subtracting 𝑎 from the center.
Ellipses
Identify the center, 𝑎, and the vertices.
5) 𝑥2
16+
𝑦2
36= 1 6)
𝑥2
16+ 𝑦2 = 1
Ellipses
Identify the center, 𝑎, and the vertices.
7) 𝑥+1 2
36+
𝑦+1 2
25= 1
Ellipses
The focal points (foci) of an ellipse are a set distance 𝑐 away from the center along the major
axis. For either major axis (↔, ↕)
𝑏2 = 𝑎2 − 𝑐2 or 𝑐 = 𝑎2 − 𝑏2
Ellipses
Identify the foci.
8) 𝑥2
9+
𝑦2
25= 1 9)
𝑥2
16+ 𝑦2 = 1
Ellipses
Identify the center, vertices, and foci. GRAPH.
10) 𝑥2
9+
𝑦2
25= 1 11)
𝑥2
100+
𝑦2
64= 1
Ellipses
Identify the center, vertices, and foci. GRAPH.
12) 𝑥+2 2
25+
𝑦2
16= 1
Ellipses
Use the information provided to write the standard
form equation of the ellipse.
13) Center: (0,0)
Vertex: (6,0)
Focus: (3,0)
Ellipses
Use the information provided to write the standard
form equation of the ellipse.
13) Foci: (0,6), (0, −6)
Length of major axis: 20