Grade 11 → Coordinate Geometry → Conic Sections ↓
Hyperbola
In the world of mathematics and coordinate geometry, conic sections are the curves obtained by intersecting a plane with a cone. These conic sections include circles, ellipses, parabolas, and hyperbolas. Out of these, the hyperbola is a fascinating figure that is used in many fields ranging from architecture to physics. appears in many real-world applications. In this guide, we'll explore the hyperbola, understand its equation, properties, and see how it can be represented graphically.
What is a hyperbola?
A hyperbola is a type of conic section that occurs when a plane intersects both napes (top and bottom sides) of a double cone, such that the angle of the plane with the vertical axis is the angle between the generator of the cone and the vertical axis is less than. This produces two separate curves that are mirror images of each other, called the branches of the hyperbola.
Standard equation of hyperbola
The standard form of the equation of a hyperbola centered at the origin is given as:
(frac{x^2}{a^2} - frac{y^2}{b^2} = 1) (Horizontal hyperbola) (frac{y^2}{b^2} - frac{x^2}{a^2} = 1) (Vertical hyperbola)
In these equations, (a) and (b) are real numbers that determine the shape and orientation of the hyperbola:
- (a) – semi-major axis length.
- (b) – semi-minor axis length.
Orientation of hyperbola
Depending on whether the axis ratio is horizontal or vertical, the hyperbola can take two shapes:
- If the (x^2) term is positive and the (y^2) term is negative, the hyperbola opens left and right. It is a horizontal hyperbola.
- If the (y^2) term is positive and the (x^2) term is negative, the hyperbola opens up and down. This is a vertical hyperbola.
Visual example of hyperbola with SVG
Below is a representation of a hyperbola using graphical elements. Imagine two opposite curves diverging from each other.
The graph above shows a horizontal hyperbola centered around the origin, with two branches extending left and right. The lines intersecting at the center are the coordinate axes. The shape formed by the curve is characteristic of a hyperbola.
Focus and transverse axis
In a hyperbola, the foci (singular: focus) are the two fixed points used in the formal definition of a hyperbola. The distance of each point on a hyperbola from one focus subtracted from the other focus is constant. The transverse axis is the line segment that is perpendicular to the hyperbola's axis. passes through the centre and the two foci.
For a horizontal hyperbola, the focuses are located at ((c, 0)) and ((-c, 0)) along the x-axis, where (c) is the distance of each focus from the centre, Which is calculated as follows:
c = sqrt{a^2 + b^2}
The length of the transverse axis is given by (2a), which represents twice the value of the horizontal distance from the centre to the vertex.
Visual example of focus and transverse axis
In the diagram above, the red points (F_1) and (F_2) are the foci of the hyperbola. These points are central to the definition of a hyperbola. The gray line represents the transverse axis.
Conjugate axis
The conjugate axis is the line segment perpendicular to the transverse axis, which passes through the center of the hyperbola. Its length is (2b) and it lies along the other axis by which the hyperbola does not open.
For a horizontal hyperbola the conjugate axis is vertical, and for a vertical hyperbola it is horizontal.
Visual example of conjugate axis
Here, the blue line represents the conjugate axis. Note that it is perpendicular to the transverse axis, which forms the framework of the definition of a hyperbola.
Eccentricity of hyperbola
The eccentricity of a hyperbola (denoted as (e)) is a measure of its "flatness" and is defined as the ratio of the distance between the foci to the distance to the transverse axis.
e = frac{c}{a}
For a hyperbola the eccentricity is always greater than 1, because the distance between the foci is greater than the length of the transverse axis.
Practical examples of hyperbola
Hyperbolas are found in a variety of real-life applications and natural phenomena:
- Radio antenna design: The reflective properties of hyperbolas help in designing directional radio antennas.
- Sonic booms: Patterns produced by objects traveling at supersonic speeds create hyperbolic shock waves.
- Navigation systems: Hyperbola principles are used in older navigation systems to determine position based on the time difference in signal reception.
Examples of equations depicting a hyperbola
- Find the equation of the hyperbola with focus at ((pm5, 0)) and vertex at ((pm3, 0)).
Given the vertex ((pm3, 0)), we know (a = 3). With focus at ((pm5, 0)), then (c = 5). Using the relation:
c^2 = a^2 + b^2 25 = 9 + b^2 b^2 = 16
The equation of the hyperbola is:
(frac{x^2}{9} - frac{y^2}{16} = 1)
- Consider a hyperbola given by the equation (frac{y^2}{49} - frac{x^2}{16} = 1). Identify the orientation, focus, and eccentricity.
This is a vertical hyperbola because the (y^2) term is positive. Here, (b = 7) and (a = 4), so we calculate (c):
c^2 = a^2 + b^2 c^2 = 16 + 49 c = sqrt{65}
The foci are at ((0, pm sqrt{65})), and the eccentricity is:
e = frac{sqrt{65}}{4}
Conclusion
Hyperbolas are an essential conic section with interesting properties and applications. By understanding their mathematical representation, geometry, and the role of focuses and axes, we can appreciate the beauty and utility of hyperbolas. Their presence in fields such as engineering and astronomy highlights their importance. and versatility. Through examples and visualizations, we gain deeper insight into the fascinating nature of hyperbolas.