Chapter 10: Problem 20
Graph each hyperbola. Give the domain, range, center, vertices, foci, and equations of the asymptotes for each figure. $$\frac{(y+5)^{2}}{4}-\frac{(x-1)^{2}}{16}=1$$
Short Answer
Expert verified
Center: (1, -5), Vertices: (1, -3) and (1, -7), Foci: (1, -5+2sqrt{5}) and (1, -5-2sqrt{5}), Asymptotes: y = -5 ± (1/2)(x - 1), Domain: (-∞, ∞), Range: (-∞, -7) ∪ (-3, ∞)
Step by step solution
01
- Identify the Standard Form
The given equation of the hyperbola is: \[\frac{(y+5)^{2}}{4}-\frac{(x-1)^{2}}{16}=1\]This is in the standard form of \[\frac{(y-k)^{2}}{a^{2}}-\frac{(x-h)^{2}}{b^{2}}=1\]The hyperbola is vertical because the \(y\)-term is positive and comes first.
02
- Identify the Center
Compare the given equation to the standard form. Here, \((h, k)\) is the center of the hyperbola.So, we have \(h = 1\) and \(k = -5\). The center is \((1, -5)\).
03
- Find the Vertices
For a vertical hyperbola, the vertices are \((h, k+a)\) and \((h, k-a)\).Using \(a^{2} = 4\), we get \(a = 2\).So, the vertices are \((1, -5+2) = (1, -3)\) and \((1, -5-2) = (1, -7)\).
04
- Find the Foci
The foci are found using the formula \(c^{2} = a^{2} + b^{2}\).Here, \(a^{2} = 4\) and \(b^{2} = 16\).So, \(c^{2} = 4 + 16 = 20\) which means \(c = \sqrt{20} = 2\sqrt{5}\).Therefore, the foci are at \((1, -5+2\sqrt{5})\) and \((1, -5-2\sqrt{5})\).
05
- Find the Equations of the Asymptotes
For a vertical hyperbola, the asymptotes are given by \(y - k = \pm \frac{a}{b}(x - h)\).Substituting \(a = 2\), \(b = 4\), \(h = 1\), and \(k = -5\), the equations of the asymptotes are:\[y + 5 = \pm \frac{2}{4}(x - 1)\]Simplifying, we get:\[y + 5 = \pm \frac{1}{2}(x - 1)\]Or,\[y = -5 \pm \frac{1}{2}(x - 1)\].
06
- Determine the Domain
For a hyperbola that opens vertically, the domain is all real numbers, \((\-\infty, \infty)\).
07
- Determine the Range
The range includes all values of \(y\) such that \(y < k - a\) or \(y > k + a\).Substituting \(k = -5\) and \(a = 2\), the range is \((\-\infty, -7) \cup (-3, \infty)\).
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Domain and Range of a Hyperbola
Understanding the domain and range of a hyperbola is crucial for graphing it correctly.
For a vertical hyperbola, like the one given by the equation \(\frac{(y+5)^{2}}{4}-\frac{(x-1)^{2}}{16}=1\), let's break down both terms a bit more.
Simply put:
For a vertical hyperbola, like the one given by the equation \(\frac{(y+5)^{2}}{4}-\frac{(x-1)^{2}}{16}=1\), let's break down both terms a bit more.
- Domain: The domain of a hyperbola that opens vertically is all real numbers, which is written as \((-fty, +fty)\). This is because, for any real value of \(x\), there is a corresponding \(y\) value that satisfies the hyperbola equation.
- Range: The range of this hyperbola is all \(y\) values that make \(y < k - a\) or \(y > k + a\). For our equation, with \(k = -5\) and \(a = 2\), we get the intervals \((y < -7) \cup (y > -3)\).
Simply put:
- The domain tells you how wide the hyperbola stretches horizontally.
- The range tells you the vertical stretch.
Asymptotes of a Hyperbola
Asymptotes are crucial for understanding the hyperbola's behavior, especially as it moves away from the center. They help guide your graph.
For the equation \(\frac{(y+5)^{2}}{4}-\frac{(x-1)^{2}}{16}=1\), we'll determine the equations of the asymptotes like this:
Remember:
For the equation \(\frac{(y+5)^{2}}{4}-\frac{(x-1)^{2}}{16}=1\), we'll determine the equations of the asymptotes like this:
- Note that it is a vertical hyperbola.
- The asymptote equations for vertical hyperbolas are given by:
\(y - k = \pm \frac{a}{b}(x - h)\). - Using values \(a = 2\), \(b = 4\), \(h = 1\), and \(k = -5\), the asymptote equations become:
\(y + 5 = \pm \frac{2}{4}(x - 1)\). - After simplification, we have:
\(y + 5 = \pm \frac{1}{2}(x - 1)\) or \(y = -5 \pm \frac{1}{2}(x - 1) \).
Remember:
- Asymptotes indicate the lines that the hyperbola approaches, but never touches.
- They help define the hyperbola's direction and shape.
Vertices of a Hyperbola
The vertices are vital anchor points that provide crucial information about the hyperbola's structure.
For a vertical hyperbola like our given equation \(\frac{(y+5)^{2}}{4}-\frac{(x-1)^{2}}{16}=1\), the vertices are found using the formula \(h, k \pm \ a\).
The vertices tell us where the hyperbola crosses its axis of symmetry.
Key Points:
For a vertical hyperbola like our given equation \(\frac{(y+5)^{2}}{4}-\frac{(x-1)^{2}}{16}=1\), the vertices are found using the formula \(h, k \pm \ a\).
- Formula: For our hyperbola, where \(h = 1\), \(k = -5\), and \(a = 2\), the vertices are computed as follows:
- (1, -5 + 2) = (1, -3)
- (1, -5 - 2) = (1, -7)
The vertices tell us where the hyperbola crosses its axis of symmetry.
Key Points:
- The distance between the center and each vertex is\( a = 2 \).
- The vertices lie directly above and below the center in a vertical hyperbola.