Chapter 8: Problem 42
Find the eccentricity e of each ellipse or hyperbola. $$8 x^{2}-y^{2}=16$$
Short Answer
Expert verified
The eccentricity \(e\) of the hyperbola is 3.
Step by step solution
01
Recognize the Conic Section
The equation given is \(8x^2 - y^2 = 16\). This has the form \(Ax^2 - By^2 = C\), where \(A\) and \(B\) are positive constants. This is the standard form of a hyperbola due to the subtraction sign between \(x^2\) and \(y^2\) terms.
02
Convert to Standard Form of Hyperbola
The standard form of a hyperbola is \(\frac{x^2}{a^2} - \frac{y^2}{b^2} = 1\). Start by dividing the entire equation by 16 to get \(\frac{8x^2}{16} - \frac{y^2}{16} = 1\), which simplifies to \(\frac{x^2}{2} - \frac{y^2}{16} = 1\). This gives \(a^2 = 2\) and \(b^2 = 16\).
03
Determine Values of a, b, and c for the Hyperbola
From \(a^2 = 2\), we find \(a = \sqrt{2}\). From \(b^2 = 16\), we find \(b = 4\). In a hyperbola, \(c\) is found using the relationship \(c^2 = a^2 + b^2\). Substitute the known values to find \(c^2 = 2 + 16 = 18\), thus \(c = \sqrt{18} = 3\sqrt{2}\).
04
Find the Eccentricity of the Hyperbola
For hyperbolas, the eccentricity \(e\) is given by \(e = \frac{c}{a}\). Substitute the values \(c = 3\sqrt{2}\) and \(a = \sqrt{2}\) to find \(e = \frac{3\sqrt{2}}{\sqrt{2}} = 3\).
Unlock Step-by-Step Solutions & Ace Your Exams!
-
Full Textbook Solutions
Get detailed explanations and key concepts
-
Unlimited Al creation
Al flashcards, explanations, exams and more...
-
Ads-free access
To over 500 millions flashcards
-
Money-back guarantee
We refund you if you fail your exam.
Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!
Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Eccentricity
In the world of conic sections, eccentricity is a measure that determines how much a curve deviates from being circular. It plays a crucial role in defining the shape of ellipses and hyperbolas. Eccentricity is represented by the symbol \( e \), and its value varies depending on the type of conic section you are dealing with.
- For an ellipse, the eccentricity is between 0 and 1, which indicates how "stretched" it is compared to a perfect circle.
- For a hyperbola, like in our exercise, the eccentricity is greater than 1, showing how the two branches are open and extend outwards.
- A perfect circle, on the other hand, has an eccentricity of 0.
Hyperbola
A hyperbola is one of the fascinating conic sections you will encounter in mathematics. It is characterized by two distinct branches that mirror each other, forming a symmetrical shape about a central axis. Hyperbolas are defined by an equation that typically has a subtraction sign between its squared terms. In our case, the equation is \( 8x^2 - y^2 = 16 \).
- This subtraction is key, distinguishing it from an ellipse, which uses addition.
- A hyperbola's defining feature is its two disconnected curves, which resemble open-ended U-shapes or bowls facing away from each other.
Standard Form of Hyperbola
The standard form of a hyperbola equation makes it easier to handle and interpret. It is written as:\[ \frac{x^2}{a^2} - \frac{y^2}{b^2} = 1 \]This standard form involves:
- \( a^2 \) and \( b^2 \), which are constants derived from the hyperbola’s equation.
- "\( - \)" sign that separates the two fractions, indicating that the graph will be a hyperbola.