key term - Minor axis

Definition

The minor axis is the shorter diameter of an ellipse, perpendicular to the major axis at the center. This axis plays a crucial role in defining the shape and size of the ellipse, determining how 'stretched' or 'squished' it appears. While the major axis represents the longest distance across the ellipse, the minor axis provides insight into its width and is essential for understanding the overall geometry of ellipses.

5 Must Know Facts For Your Next Test

1. The minor axis divides the ellipse into two equal halves and runs perpendicular to the major axis at the center point.
2. In a standard form equation for an ellipse, the lengths of the major and minor axes can be derived from the coefficients in the equation, specifically from 'a' and 'b'.
3. For horizontal ellipses, the minor axis is vertical, while for vertical ellipses, it is horizontal.
4. The length of the minor axis is always shorter than that of the major axis, indicating that it provides less 'stretch' to the shape of the ellipse.
5. The coordinates of endpoints of the minor axis can be found using the center coordinates along with half of its length in both positive and negative directions.

Review Questions

• How does the minor axis relate to other characteristics of an ellipse, such as its major axis and foci?
  • The minor axis is directly related to other features of an ellipse, particularly the major axis and foci. While the major axis defines the longest distance across the ellipse, determining its overall length, the minor axis provides information about its width. The foci are positioned along the major axis, influencing how 'stretched' or 'squished' the ellipse appears. Together, these elements help define the overall geometry of ellipses.
• Describe how you would find the lengths of both axes from the standard form equation of an ellipse.
  • To find the lengths of both axes from a standard form equation like $$\frac{(x-h)^2}{a^2} + \frac{(y-k)^2}{b^2} = 1$$, identify 'a' and 'b'. Here, 'a' represents half of the length of the major axis if 'a > b', while 'b' represents half of the length of the minor axis. Conversely, if 'b > a', then 'b' is half of the length of the major axis. These values allow you to determine how elongated or compacted an ellipse is based on its axes.
• Analyze how changes to the length of the minor axis affect the overall shape and properties of an ellipse.
  • Changes to the length of the minor axis significantly impact an ellipse's shape and properties. A shorter minor axis results in a more elongated shape, giving it a more pronounced oval appearance. Conversely, a longer minor axis brings it closer to a circular form. Additionally, altering this length affects calculations related to eccentricity; as it increases relative to the major axis, eccentricity decreases, indicating that the ellipse becomes less stretched. This relationship between axes influences how ellipses are represented in real-world applications such as astronomy and engineering.

Related terms

major axis:

The longest diameter of an ellipse, running through both foci and the center, which helps determine the overall length of the ellipse.

foci:

Two fixed points located along the major axis of an ellipse, which help define its shape and properties.

eccentricity: A measure of how much an ellipse deviates from being circular, calculated using the lengths of the major and minor axes.