# The Eccentricity of an Ellipse

In geometry, an ellipse is a closed curve in a plane that "roughly" resembles a circle. More precisely, an ellipse is a curve that is the locus of all points for which the sum of the distances to two foci is a constant. An ellipse is also sometimes called an oval. The word "ellipse" comes from the Greek word "?λλειψις" (élleipsis), which means "omission."

The eccentricity of an ellipse is a measure of how "flattened" or elongated the ellipse is. An ellipse with a large eccentricity is more elongated than one with a small eccentricity. The eccentricity of an ellipse can be any value greater than or equal to 0 and less than or equal to 1. If the eccentricity is 0, then the ellipse is a circle. If the eccentricity is 1, then the ellipse is a line segment.

The eccentricity of an ellipse can be calculated using the following formula: e = c/a where c is the distance between the foci and a is the length of the semi-major axis.

In conclusion, the eccentricity of an ellipse measures how "flattened" or elongated the ellipse is. An ellipse with a large eccentricity is more elongated than one with a small eccentricity. The eccentricity of an ellipse can be any value greater than or equal to 0 and less than or equal to 1. If you want to calculate the eccentricity of an ellipse, use the formula e = c/a where c is the distance between the foci and a is the length of the semi-major axis.

## FAQ

### Which of the following is true about the eccentricity of the ellipse?

The eccentricity of the ellipse is a measure of how "flat" or "stretched out" the ellipse is. It is represented by the letter e, and is equal to the ratio of the distance between the foci of the ellipse and the major axis length. A value of 0 indicates a perfect circle, while values greater than 0 indicate increasingly "flattened" ellipses. The eccentricity can also be thought of as the ratio of the minor axis length to the major axis length.

### What is the eccentricity formula?

The eccentricity formula is used to calculate the eccentricity of an ellipse. It is represented by the letter e, and is equal to the ratio of the distance between the foci of the ellipse and the major axis length. A value of 0 indicates a perfect circle, while values greater than 0 indicate increasingly "flattened" ellipses. The eccentricity can also be thought of as the ratio of the minor axis length to the major axis length.

### What is the difference between the major axis and the minor axis?

The major axis is the longest diameter of an ellipse, while the minor axis is the shortest diameter. The major axis is equal to 2 times the radius of the ellipse, while the minor axis is equal to the square root of the difference between the major axis and the minor axis. The ratio of the major axis to the minor axis is called the eccentricity of the ellipse.

### Why is eccentricity 0 and 1?

Eccentricity 0 indicates a perfect circle, while eccentricity 1 indicates a perfectly "flattened" ellipse. The eccentricity can also be thought of as the ratio of the minor axis length to the major axis length. A value of 0 indicates a perfect circle, while values greater than 0 indicate increasingly "flattened" ellipses.

### Can eccentricity be equal to 1?

Yes, eccentricity can be equal to 1. This indicates a perfectly "flattened" ellipse. The eccentricity can also be thought of as the ratio of the minor axis length to the major axis length. A value of 0 indicates a perfect circle, while values greater than 0 indicate increasingly "flattened" ellipses.