Chapter 11: Problem 42
(a) For the hyperbola $$\frac{x^{2}}{9}-\frac{y^{2}}{16}=1$$ determine the values of \(a, b,\) and \(c,\) and find the coordinates of the foci \(F_{1}\) and \(F_{2} .\) (b) Show that the point \(P\left(5, \frac{16}{3}\right)\) lies on this hyperbola. (c) Find \(d\left(P, F_{1}\right)\) and \(d\left(P, F_{2}\right)\) . (d) Verify that the difference between \(d\left(P, F_{1}\right)\) and \(d\left(P, F_{2}\right)\) is 2\(a .\)
Short Answer
Step by step solution
Identify the standard form and values of a, b
Find c value using a and b
Determine coordinates of foci F1 and F2
Verify if point P lies on the hyperbola
Calculate distance d(P, F1)
Calculate distance d(P, F2)
Verify difference of distances
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Foci of Hyperbola
In the context of the given exercise, we have a hyperbola of the form \( \frac{x^2}{a^2} - \frac{y^2}{b^2} = 1 \). For this type of hyperbola, the foci are given by the coordinates \((\pm c, 0)\), where \(c\) is the distance from the center to each focus on the x-axis.
To calculate \(c\), we use the relationship \(c^2 = a^2 + b^2\). Put simply:
- Find \(a\) and \(b\) from the hyperbola equation.
- Calculate \(c^2\) using \(c^2 = a^2 + b^2\).
- Find \(c\) by taking the square root of \(c^2\).
Equation of Hyperbola
The equation \( \frac{x^2}{9} - \frac{y^2}{16} = 1 \) indicates a hyperbola opening horizontally because the \(x^2\) term is positive and appears first.
Here are the crucial points to understand about this form:
- \(a^2\) is under the \(x^2\) term, setting the width of the hyperbola along the x-axis.
- \(b^2\) is under the \(y^2\) term, determining the height of the branches along the y-axis.
- The transverse axis is horizontal since the \(x^2\) term is first.
Distance Formula
The distance formula is given by:
\[d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2}\]
Let's apply this formula:
- First, substitute \(x_1, y_1\) and \(x_2, y_2\) with the coordinates of the points you're interested in.
- Square the differences in x-coordinates and y-coordinates, add them, and take the square root.
- This gives the direct distance between two points.
Coordinate Geometry
Within the scope of hyperbolas, coordinate geometry is used to:
- Plot the hyperbola based on its equation and understand its shape.
- Determine important points like vertices, foci, and co-vertices.
- Solve for distances and verify relationships between points—like in this problem where checking point \(P\)'s position relative to the hyperbola was essential.
- The hyperbola is centered at the origin \((0, 0)\).
- It stretches horizontally with vertices and foci aligned along the x-axis.
- The calculated distances and points respect the geometric rules of a hyperbola.