Chapter 7
A Graphical Approach to College Algebra · 324 exercises
Problem 77
Write the equation in standard form for a hyperbola centered at ( \(h, k\) ). Identify the center and vertices. \(x^{2}-2 x-y^{2}+2 y=4\)
6 step solution
Problem 78
Write the equation in standard form for a hyperbola centered at ( \(h, k\) ). Identify the center and vertices. \(y^{2}+4 y-x^{2}+2 x=6\)
5 step solution
Problem 78
Write an equation for each parabola with vertex at the origin. $$\text { Focus }\left(0, \frac{1}{4}\right)$$
4 step solution
Problem 78
Solve each nonlinear system of equations analytically for all real solutions. $$\begin{aligned} &x^{2}+3 x y+y^{2}=5\\\ &x^{2}-2 x y-y^{2}=-7 \end{aligned}$$
9 step solution
Problem 79
Write the equation in standard form for a hyperbola centered at ( \(h, k\) ). Identify the center and vertices. \(3 y^{2}+24 y-2 x^{2}+12 x+24=0\)
5 step solution
Problem 79
Write an equation for each parabola with vertex at the origin. Through \((2,-2 \sqrt{2}) ;\) opening to the right
5 step solution
Problem 79
Use substitution to solve the nonlinear system of equations in three variables. Note that solutions are ordered triples. $$\begin{aligned} 2 x^{2}+y^{2}+3 z^{2} &=3 \\ 2 x+y-z &=1 \\ x+y &=0 \end{aligned}$$
6 step solution
Problem 80
Write an equation for each parabola with vertex at the origin. Through \((\sqrt{3}, 3) ;\) opening upward
5 step solution
Problem 80
Use substitution to solve the nonlinear system of equations in three variables. Note that solutions are ordered triples. $$\begin{aligned} x^{2}+y^{2}+z^{2} &=4 \\ x+y+z &=2 \\ x-y &=0 \end{aligned}$$
7 step solution
Problem 80
Write the equation in standard form for a hyperbola centered at ( \(h, k\) ). Identify the center and vertices. \(4 x^{2}+16 x-9 y^{2}+18 y=29\)
7 step solution
Problem 81
Write the equation in standard form for a hyperbola centered at ( \(h, k\) ). Identify the center and vertices. \(x^{2}-6 x-2 y^{2}+7=0\)
6 step solution
Problem 81
Write an equation for each parabola with vertex at the origin. Through \((\sqrt{10},-5) ;\) opening downward
4 step solution
Problem 81
Graph the solution set of each system of inequalities by hand. $$\begin{aligned} &\frac{x^{2}}{16}+\frac{y^{2}}{4} \leq 1\\\ &x^{2}-y^{2} \geq 1 \end{aligned}$$
5 step solution
Problem 82
Write the equation in standard form for a hyperbola centered at ( \(h, k\) ). Identify the center and vertices. \(y^{2}+8 y-3 x^{2}+13=0\)
4 step solution
Problem 82
Write an equation for each parabola with vertex at the origin. Through \((-3,3) ;\) opening to the left
4 step solution
Problem 82
Graph the solution set of each system of inequalities by hand. $$\begin{aligned} &\frac{x^{2}}{4}+\frac{y^{2}}{9} \leq 1\\\ &\frac{y^{2}}{4}-\frac{x^{2}}{9} \leq 1 \end{aligned}$$
6 step solution
Problem 83
Write the equation in standard form for a hyperbola centered at ( \(h, k\) ). Identify the center and vertices. \(4 y^{2}+32 y-5 x^{2}-10 x+39=0\)
5 step solution
Problem 83
Write an equation for each parabola with vertex at the origin. Through \((2,-4)\); symmetric with respect to the \(y\) -axis
4 step solution
Problem 83
Graph the solution set of each system of inequalities by hand. $$\begin{array}{c} 4 x^{2}-y^{2}>4 \\ 9 x^{2}+4 y^{2}>36 \end{array}$$
6 step solution
Problem 84
Write the equation in standard form for a hyperbola centered at ( \(h, k\) ). Identify the center and vertices. \(5 x^{2}+10 x-7 y^{2}+28 y=58\)
7 step solution
Problem 84
Write an equation for each parabola with vertex at the origin. Through \((3,2) ;\) symmetric with respect to the \(x\) -axis
5 step solution
Problem 84
Graph the solution set of each system of inequalities by hand. $$\begin{aligned} &16 x^{2}+9 y^{2}<144\\\ &(x-1)^{2}+(y+1)^{2}>1 \end{aligned}$$
5 step solution
Problem 85
For individual or group investigation. Consider the ellipse and hyperbola defined by $$\frac{x^{2}}{16}+\frac{y^{2}}{12}=1 \quad \text { and } \quad \frac{x^{2}}{4}-\frac{y^{2}}{12}=1$$ respectively. Find the foci of the ellipse. Call them \(F_{1}\) and \(F_{2}\).
4 step solution
Problem 85
Find an equation of a parabola that satisfies the given conditions. Focus \((0,2) ;\) vertex \((0,1)\)
4 step solution
Problem 85
Graph the solution set of each system of inequalities by hand. $$\begin{aligned} &\frac{(x-1)^{2}}{9}+\frac{y^{2}}{4} \leq 1\\\ &\frac{x^{2}}{4}-\frac{(y+1)^{2}}{9} \geq 1 \end{aligned}$$
6 step solution
Problem 86
For individual or group investigation. Consider the ellipse and hyperbola defined by $$\frac{x^{2}}{16}+\frac{y^{2}}{12}=1 \quad \text { and } \quad \frac{x^{2}}{4}-\frac{y^{2}}{12}=1$$ respectively. Graph the ellipse with your calculator, and trace to find the coordinates of several points on the ellipse.
5 step solution
Problem 86
Find an equation of a parabola that satisfies the given conditions. Focus \((-1,2) ;\) vertex \((3,2)\)
4 step solution
Problem 86
Graph the solution set of each system of inequalities by hand. $$\begin{aligned} &\frac{(x-2)^{2}}{36}+\frac{(y+2)^{2}}{25} \leq 1\\\ &\frac{(x+1)^{2}}{9}+\frac{(y-3)^{2}}{25} \leq 1 \end{aligned}$$
6 step solution
Problem 87
Find an equation of a parabola that satisfies the given conditions. Focus \((0,0) ;\) directrix \(x=-2\)
4 step solution
Problem 87
Solve each application. The orbit of Mars around the sun is an ellipse with equation $$\frac{x^{2}}{5013}+\frac{y^{2}}{4970}=1$$ where \(x\) and \(y\) are measured in millions of miles. Approximate the eccentricity \(e\) of this ellipse.
6 step solution
Problem 88
Find an equation of a parabola that satisfies the given conditions. Focus \((2,1) ;\) directrix \(x=-1\)
5 step solution
Problem 88
Solve each application. Neptune and Pluto both have elliptical orbits with the sun at one focus. Neptune's orbit has \(a=30.1\) astronomical units (AU) and eccentricity \(e=0.009,\) whereas Pluto's orbit has \(a=39.4\) and \(e=0.249 .(1 \mathrm{AU}\) is equal to the average distance from Earth to the sun and is approximately \(149,600,000\) kilometers.) (Source: Zeilik, M., S. Gregory, and E. Smith, Introductory Astronomy and Astrophysics, Saunders College Publishers.)(a) Position the sun at the origin, and determine an equation for each orbit. (b) Graph both equations on the same coordinate axes. Use the window \([-60,60]\) by \([-40,40]\)
7 step solution
Problem 89
Find an equation of a parabola that satisfies the given conditions. Focus \((-1,3) ;\) directrix \(y=7\)
6 step solution
Problem 90
Find an equation of a parabola that satisfies the given conditions. Focus \((1,2) ;\) directrix \(y=4\)
5 step solution
Problem 90
Solve each application. The famous Halley's comet last passed Earth in February 1986 and will next return in \(2062 .\) Halley's comet has an elliptical orbit of eccentricity 0.9673 with the sun at one of the foci. The greatest distance of the comet from the sun is 3281 million miles. (Source: The World Almanac and Book of Facts. Find the least distance between Halley's comet and the sun.
5 step solution
Problem 91
Solve each problem. A patient's kidney stone is placed 12 units away from the source of the shock waves of a lithotripter. The lithotripter is based on an ellipse with a minor axis that measures 16 units. Find an equation of an ellipse that would satisfy this situation.
5 step solution
Problem 91
Find an equation of a parabola that satisfies the given conditions. Horizontal axis; vertex \((-2,3) ;\) passing through \((-4,0)\)
4 step solution
Problem 91
Solve each application. Orbit of Earth The orbit of Earth is an ellipse with the sun at one focus. The distance between Earth and the sun ranges from 91.4 to 94.6 million miles. (Source: The World Almanac and Book of Facts.) Estimate the eccentricity of Earth's orbit.
5 step solution
Problem 92
Solve each problem. The orbit of Venus is an ellipse, with the sun at one focus. An approximate equation for the orbit is $$\frac{x^{2}}{5013}+\frac{y^{2}}{4970}=1$$ where \(x\) and \(y\) are measured in millions of miles. (a) Approximate the length of the major axis. (b) Approximate the length of the minor axis.
4 step solution
Problem 92
Find an equation of a parabola that satisfies the given conditions. Horizontal axis; vertex \((-1,2) ;\) passing through \((2,3)\)
5 step solution
Problem 93
Solve each problem. The Roman Colosseum is an ellipse with major axis 620 feet and minor axis 513 feet. Approximate the distance between the foci of this ellipse.
6 step solution
Problem 93
Graph each parabola by hand, and check using a graphing calculator. Give the vertex, axis, domain, and range. $$y=(x+3)^{2}-4$$
7 step solution
Problem 94
Graph each parabola by hand, and check using a graphing calculator. Give the vertex, axis, domain, and range. $$y=(x-5)^{2}-4$$
7 step solution
Problem 95
Graph each parabola by hand, and check using a graphing calculator. Give the vertex, axis, domain, and range. $$y=-2(x+3)^{2}+2$$
7 step solution
Problem 96
Graph each parabola by hand, and check using a graphing calculator. Give the vertex, axis, domain, and range. $$y=\frac{2}{3}(x-2)^{2}-1$$
7 step solution
Problem 97
Graph each parabola by hand, and check using a graphing calculator. Give the vertex, axis, domain, and range. $$y=x^{2}-2 x+3$$
7 step solution
Problem 98
Graph each parabola by hand, and check using a graphing calculator. Give the vertex, axis, domain, and range. $$y=x^{2}+6 x+5$$
7 step solution
Problem 99
Solve each problem. Structure of an Atom In \(1911,\) Ernest Rutherford discovered the basic structure of the atom by "shooting" positively charged alpha particles with a speed of \(10^{7}\) meters per second at a piece of gold foil \(6 \times 10^{-7}\) meter thick. Only a small percentage of the alpha particles struck a gold nucleus head-on and were deflected directly back toward their source. The rest of the particles often followed a hyperbolic trajectory because they were repelled by positively charged gold nuclei. Thus, Rutherford proposed that the atom was composed of mostly empty space and a small, dense nucleus. The figure shows an alpha particle \(A\) initially approaching a gold nucleus \(N\) and being deflected at an angle \(\theta=90^{\circ}\) \(N\) is located at a focus of the hyperbola, and the trajectory of \(A\) passes through a vertex of the hyperbola. (a) Determine the equation of the trajectory of the alpha particle if \(d=5 \times 10^{-14}\) meter. (b) Approximate the minimum distance between the centers of the alpha particle and the gold nucleus. (GRAPH CAN'T COPY)
6 step solution
Problem 99
Graph each parabola by hand, and check using a graphing calculator. Give the vertex, axis, domain, and range. $$y=2 x^{2}-4 x+5$$
7 step solution
Problem 100
Suppose a hyperbola has center at the origin, foci at \(F^{\prime}(-c, 0)\) and \(F(c, 0),\) and equation $$\left|d\left(P, F^{\prime}\right)-d(P, F)\right|=2 a$$ Let \(b^{2}=c^{2}-a^{2},\) and show that the points on the hyperbola satisfy the equation $$\frac{x^{2}}{a^{2}}-\frac{y^{2}}{b^{2}}=1$$
9 step solution