Exercises 21.4, page 586

1. $F (5, 0), x = - 5$ $F (5, 0), x = - 5$
3. $F (0, - \frac{3}{2}), y = \frac{3}{2}$ $F (0, - \frac{3}{2}), y = \frac{3}{2}$
5. $F (1, 0), x = - 1$ $F (1, 0), x = - 1$
7. $F (- 16, 0), x = 16$ $F (- 16, 0), x = 16$
9. $F (0, 18), y = - 18$ $F (0, 18), y = - 18$
11. $F (0, - 1), y = 1$ $F (0, - 1), y = 1$
13. $F (\frac{5}{8}, 0), x = - \frac{5}{8}$ $F (\frac{5}{8}, 0), x = - \frac{5}{8}$
15. $F (0, \frac{25}{48}), y = - \frac{25}{48}$ $F (0, \frac{25}{48}), y = - \frac{25}{48}$
17. $y^{2} = 12 x$ $y^{2} = 12 x$
19. $x^{2} = - 2 y$ $x^{2} = - 2 y$
21. $x^{2} = 0.64 y$ $x^{2} = 0.64 y$
23. $x^{2} = 336 y$ $x^{2} = 336 y$
25. $x^{2} = \frac{1}{8} y$ $x^{2} = \frac{1}{8} y$
27. $y^{2} = \frac{25}{3} x$ $y^{2} = \frac{25}{3} x$
29. $y^{2} = 3 x$ $y^{2} = 3 x$
31. $(0, 0), (8, - 4)$ $(0, 0), (8, - 4)$
33. $y^{2} - 2 y - 12 x + 37 = 0$ $y^{2} - 2 y - 12 x + 37 = 0$
35.
37.
39. 4p
41. $y^{2} = 2 x$ $y^{2} = 2 x$
43. 32.0 cm
45. 59.0 ft
47. $10^{7} km$ $10^{7} km$
49. 57.6 m
51. No (a course correction is necessary)
53. 2.16 cm from vertex
55.
57. $y^{2} = 8 x$ $y^{2} = 8 x$ or $x^{2} = 8 y$ $x^{2} = 8 y$ with vertex midway between island and shore