Chapter 11: Problem 9
Given vertices \((\pm a, 0)\) and eccentricity \(e,\) what are the coordinates of the foci of an ellipse and a hyperbola?
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Chapter 11: Problem 9
Given vertices \((\pm a, 0)\) and eccentricity \(e,\) what are the coordinates of the foci of an ellipse and a hyperbola?
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Consider the curve \(r=f(\theta)=\cos \left(a^{\theta}\right)-1.5\) where \(a=(1+12 \pi)^{1 / 2 \pi} \approx 1.78933\) (see figure). a. Show that \(f(0)=f(2 \pi)\) and find the point on the curve that corresponds to \(\theta=0\) and \(\theta=2 \pi\) b. Is the same curve produced over the intervals \([-\pi, \pi]\) and \([0,2 \pi] ?\) c. Let \(f(\theta)=\cos \left(a^{\theta}\right)-b,\) where \(a=(1+2 k \pi)^{1 / 2 \pi}, k\) is an integer, and \(b\) is a real number. Show that \(f(0)=f(2 \pi)\) and that the curve closes on itself. d. Plot the curve with various values of \(k\). How many fingers can you produce?
Graph the following equations. Then use arrows and labeled points to indicate how the curve is generated as \(\theta\) increases from 0 to \(2 \pi\). $$r=\frac{3}{1-\cos \theta}$$
Indicate the direction in which the spiral winds outward as \(\theta\) increases, where \(\theta>0 .\) Let \(a=1\) and \(a=-1\) Hyperbolic spiral: \(r=a / \theta\)
Explain why or why not Determine whether the following statements are true and give an explanation or counterexample. a. The hyperbola \(x^{2} / 4-y^{2} / 9=1\) has no \(y\) -intercepts. b. On every ellipse, there are exactly two points at which the curve has slope \(s,\) where \(s\) is any real number. c. Given the directrices and foci of a standard hyperbola, it is possible to find its vertices, eccentricity, and asymptotes. d. The point on a parabola closest to the focus is the vertex.
Find the area of the regions bounded by the following curves. The complete three-leaf rose \(r=2 \cos 3 \theta\)
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