I ’ NSTRUCTOR S S M OLUTIONS ANUAL M ULTIVARIABLE W A ILLIAM RDIS Collin County Community College T ’ C HOMAS ALCULUS T E WELFTH DITION B O W ASED ON THE RIGINAL ORK BY George B. Thomas, Jr. Massachusetts Institute of Technology R AS EVISED BY Maurice D. Weir Naval Postgraduate School Joel Hass University of California, Davis The author and publisher of this book have used their best efforts in preparing this book. These efforts include the development, research, and testing of the theories and programs to determine their effectiveness. The author and publisher make no warranty of any kind, expressed or implied, with regard to these programs or the documentation contained in this book. The author and publisher shall not be liable in any event for incidental or consequential damages in connection with, or arising out of, the furnishing, performance, or use of these programs. Reproduced by Addison-Wesley from electronic files supplied by the author. Copyright © 2010, 2005, 2001 Pearson Education, Inc. Publishing as Pearson Addison-Wesley, 75 Arlington Street, Boston, MA 02116. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Printed in the United States of America. ISBN-13: 978-0-321-60072-1 ISBN-10: 0-321-60072-X 1 2 3 4 5 6 BB 14 13 12 11 10 PREFACE TO THE INSTRUCTOR This Instructor's Solutions Manual contains the solutions to every exercise in the 12th Edition of THOMAS' CALCULUS by Maurice Weir and Joel Hass, including the Computer Algebra System (CAS) exercises. The corresponding Student's Solutions Manual omits the solutions to the even-numbered exercises as well as the solutions to the CAS exercises (because the CAS command templates would give them all away). In addition to including the solutions to all of the new exercises in this edition of Thomas, we have carefully revised or rewritten every solution which appeared in previous solutions manuals to ensure that each solution ì conforms exactly to the methods, procedures and steps presented in the text ì is mathematically correct ì includes all of the steps necessary so a typical calculus student can follow the logical argument and algebra ì includes a graph or figure whenever called for by the exercise, or if needed to help with the explanation ì is formatted in an appropriate style to aid in its understanding Every CAS exercise is solved in both the MAPLE and MATHEMATICA computer algebra systems. A template showing an example of the CAS commands needed to execute the solution is provided for each exercise type. Similar exercises within the text grouping require a change only in the input function or other numerical input parameters associated with the problem (such as the interval endpoints or the number of iterations). For more information about other resources available with Thomas' Calculus, visit http://pearsonhighered.com. Copyright © 2010 Pearson Education Inc. Publishing as Addison-Wesley. TABLE OF CONTENTS 10 Infinite Sequences and Series 569 10.1 Sequences 569 10.2 Infinite Series 577 10.3 The Integral Test 583 10.4 Comparison Tests 590 10.5 The Ratio and Root Tests 597 10.6 Alternating Series, Absolute and Conditional Convergence 602 10.7 Power Series 608 10.8 Taylor and Maclaurin Series 617 10.9 Convergence of Taylor Series 621 10.10 The Binomial Series and Applications of Taylor Series 627 Practice Exercises 634 Additional and Advanced Exercises 642 11 Parametric Equations and Polar Coordinates 647 11.1 Parametrizations of Plane Curves 647 11.2 Calculus with Parametric Curves 654 11.3 Polar Coordinates 662 11.4 Graphing in Polar Coordinates 667 11.5 Areas and Lengths in Polar Coordinates 674 11.6 Conic Sections 679 11.7 Conics in Polar Coordinates 689 Practice Exercises 699 Additional and Advanced Exercises 709 12 Vectors and the Geometry of Space 715 12.1 Three-Dimensional Coordinate Systems 715 12.2 Vectors 718 12.3 The Dot Product 723 12.4 The Cross Product 728 12.5 Lines and Planes in Space 734 12.6 Cylinders and Quadric Surfaces 741 Practice Exercises 746 Additional Exercises 754 13 Vector-Valued Functions and Motion in Space 759 13.1 Curves in Space and Their Tangents 759 13.2 Integrals of Vector Functions; Projectile Motion 764 13.3 Arc Length in Space 770 13.4 Curvature and Normal Vectors of a Curve 773 13.5 Tangential and Normal Components of Acceleration 778 13.6 Velocity and Acceleration in Polar Coordinates 784 Practice Exercises 785 Additional Exercises 791 Copyright © 2010 Pearson Education Inc. Publishing as Addison-Wesley. 14 Partial Derivatives 795 14.1 Functions of Several Variables 795 14.2 Limits and Continuity in Higher Dimensions 804 14.3 Partial Derivatives 810 14.4 The Chain Rule 816 14.5 Directional Derivatives and Gradient Vectors 824 14.6 Tangent Planes and Differentials 829 14.7 Extreme Values and Saddle Points 836 14.8 Lagrange Multipliers 849 14.9 Taylor's Formula for Two Variables 857 14.10 Partial Derivatives with Constrained Variables 859 Practice Exercises 862 Additional Exercises 876 15 Multiple Integrals 881 15.1 Double and Iterated Integrals over Rectangles 881 15.2 Double Integrals over General Regions 882 15.3 Area by Double Integration 896 15.4 Double Integrals in Polar Form 900 15.5 Triple Integrals in Rectangular Coordinates 904 15.6 Moments and Centers of Mass 909 15.7 Triple Integrals in Cylindrical and Spherical Coordinates 914 15.8 Substitutions in Multiple Integrals 922 Practice Exercises 927 Additional Exercises 933 16 Integration in Vector Fields 939 16.1 Line Integrals 939 16.2 Vector Fields and Line Integrals; Work, Circulation, and Flux 944 16.3 Path Independence, Potential Functions, and Conservative Fields 952 16.4 Green's Theorem in the Plane 957 16.5 Surfaces and Area 963 16.6 Surface Integrals 972 16.7 Stokes's Theorem 980 16.8 The Divergence Theorem and a Unified Theory 984 Practice Exercises 989 Additional Exercises 997 Copyright © 2010 Pearson Education Inc. 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CHAPTER 10 INFINITE SEQUENCES AND SERIES 10.1 SEQUENCES 1. a" œ 11(cid:1)#1 œ0, a# œ "#(cid:1)#2 œ(cid:1)4", a$ œ 13(cid:1)#3 œ(cid:1)92, a% œ 14(cid:1)#4 œ(cid:1)136 2. a" œ 11! œ1, a# œ #"! œ 2", a$ œ 31! œ 61, a% œ 41! œ 214 # $ % & 3. a" œ (#(cid:1)(cid:1)1)1 œ1, a# œ (4(cid:1)(cid:1)")1 œ(cid:1)"3, a$ œ (6(cid:1)(cid:1)1)1 œ "5, a% œ (8(cid:1)(cid:1)1)1 œ(cid:1)7" 4. a" œ2(cid:2)((cid:1)1)" œ1, a# œ2(cid:2)((cid:1)1)# œ3, a$ œ2(cid:2)((cid:1)1)$ œ1, a% œ2(cid:2)((cid:1)1)% œ3 # $ % 5. a" œ #2# œ #", a# œ 22$ œ #", a$ œ 2#% œ #", a% œ 22& œ #" # $ % 6. a" œ 2(cid:1)#" œ "#, a# œ 22(cid:1)#1 œ 43, a$ œ 22(cid:1)$1 œ 87, a% œ 22(cid:1)%" œ 1165 7. a" œ1, a# œ1(cid:2) "# œ #3, a$ œ #3 (cid:2) #"# œ 74, a% œ 74 (cid:2) #"$ œ 185, a& œ 185 (cid:2) #"% œ 1361, a' œ 3623, a( œ 127, a) œ 255, a* œ 511, a"! œ 1023 64 128 256 512 " " " 8. a" œ1, a# œ "#, a$ œ ˆ3#‰ œ "6, a% œ ˆ46‰ œ #"4, a& œ ˆ#54‰ œ 1#"0, a' œ 7#"0, a( œ 50"40, a) œ 40,"320, a* œ " , a"! œ " 362,880 3,628,800 9. a" œ2, a# œ ((cid:1)1#)#(2) œ1, a$ œ ((cid:1)12)$(1) œ(cid:1)"#, a% œ ((cid:1)1)%#ˆ(cid:1)"#‰ œ(cid:1)4", a& œ ((cid:1)1)&#ˆ(cid:1)"4‰ œ 8", a' œ 1"6, a( œ(cid:1)3"#, a) œ(cid:1)6"4, a* œ 1#"8, a"! œ 2"56 " 10. a" œ(cid:1)2, a# œ 1†(#(cid:1)2) œ(cid:1)1, a$ œ 2†(3(cid:1)1) œ(cid:1)32, a% œ 3†ˆ(cid:1)4 23‰ œ(cid:1)"#, a& œ 4†ˆ(cid:1)5 #‰ œ(cid:1)52, a' œ(cid:1)3", a( œ(cid:1)2, a) œ(cid:1)", a* œ(cid:1)2, a"! œ(cid:1)" 7 4 9 5 11. a" œ1, a# œ1, a$ œ1(cid:2)1œ2, a% œ2(cid:2)1œ3, a& œ3(cid:2)2œ5, a' œ8, a( œ13, a) œ21, a* œ34, a"! œ55 " " 12. a" œ2, a# œ(cid:1)1, a$ œ(cid:1)"#, a% œ ˆ(cid:1)(cid:1)1#‰ œ "#, a& œ ˆ(cid:1)ˆ#‰"#‰ œ(cid:1)1, a' œ(cid:1)2, a( œ2, a) œ(cid:1)1, a* œ(cid:1)"#, a"! œ "# 13. a œ((cid:1)1)n(cid:2)1, nœ1, 2, á 14. a œ((cid:1)1)n, nœ1, 2, á n n (cid:0) 15. an œ((cid:1)1)n(cid:2)1n#, nœ1, 2, á 16. an œ ((cid:1)"n)#n 1 , nœ1, 2, á (cid:1) 17. a œ 2n 1 , nœ1, 2, á 18. a œ 2n(cid:1)5 , nœ1, 2, á n 3an(cid:2)2b n nan(cid:2)1b 19. a œn#(cid:1)1, nœ1, 2, á 20. a œn(cid:1)4, nœ1, 2, á n n 21. a œ4n(cid:1)3, nœ1, 2, á 22. a œ4n(cid:1)2, nœ1, 2, á n n 23. an œ 3nn(cid:2)!2, nœ1, 2, á 24. an œ 5nn(cid:0)31 , nœ1, 2, á Copyright © 2010 Pearson Education Inc. Publishing as Addison-Wesley. 570 Chapter 10 Infinite Sequences and Series 25. a œ 1(cid:2)((cid:1)1)n(cid:0)1, nœ1, 2, á 26. a œ n(cid:1)"#(cid:2)((cid:1)1)nˆ"#‰ œÚnÛ, nœ1, 2, á n # n # # 27. lim 2(cid:2)(0.1)n œ2 Ê converges (Theorem 5, #4) nÄ_ 28. lim n(cid:2)((cid:1)")n œ lim 1(cid:2) ((cid:1)1)n œ1 Ê converges nÄ_ n nÄ_ n " 29. lim "(cid:1)2n œ lim ˆ"n‰(cid:1)2 œ lim (cid:1)2 œ(cid:1)1 Ê converges nÄ_ 1(cid:2)#n nÄ_ ˆ ‰(cid:2)2 nÄ_ # n " 30. n lÄim_ 12(cid:1)n3(cid:2)È"n œn lÄim_ 2ÈŠnÈ "(cid:2)(cid:1) Š3È‹n‹ œ(cid:1)_ Ê diverges n " 31. lim "%(cid:1)5n%$ œ lim Šn%‹(cid:1)5 œ(cid:1)5 Ê converges nÄ_ n (cid:2)8n nÄ_ 1(cid:2)ˆ8‰ n 32. lim #n(cid:2)3 œ lim n(cid:2)3 œ lim " œ0 Ê converges nÄ_ n (cid:2)5n(cid:2)6 nÄ_ (n(cid:2)3)(n(cid:2)2) nÄ_ n(cid:2)# # 33. lim n (cid:1)2n(cid:2)1 œ lim (n(cid:1)1)(n(cid:1)1) œ lim (n(cid:1)1)œ_ Ê diverges nÄ_ n(cid:1)1 nÄ_ n(cid:1)1 nÄ_ " 34 lim "(cid:1)n$# œ lim Šn#‹(cid:1)n œ_ Ê diverges nÄ_ 70(cid:1)4n nÄ_ Š7#0‹(cid:1)4 n 35. lim a1(cid:2)((cid:1)1)nb does not exist Ê diverges 36. lim ((cid:1)1)nˆ1(cid:1) "‰ does not exist Ê diverges nÄ_ nÄ_ n 37. lim ˆn(cid:2)"‰ˆ1(cid:1) "‰œ lim ˆ" (cid:2) "‰ˆ1(cid:1) "‰œ " Ê converges nÄ_ #n n nÄ_ # #n n # (cid:0) 38. lim ˆ2(cid:1) "‰ˆ3(cid:2) "‰œ6 Ê converges 39. lim ((cid:1)")n 1 œ0 Ê converges nÄ_ #n #n nÄ_ #n(cid:1)1 40. lim ˆ(cid:1)"‰n œ lim ((cid:1)")n œ0 Ê converges nÄ_ # nÄ_ #n 41. lim É 2n œÉ lim 2n œÊ lim Š 2"‹œÈ2 Ê converges nÄ_ n(cid:2)1 nÄ_ n(cid:2)1 nÄ_ 1(cid:1) n 42. lim " œ lim ˆ"0‰n œ_ Ê diverges nÄ_ (0.9)n nÄ_ 9 43. lim sinˆ1 (cid:2) "‰œsinŠ lim ˆ1 (cid:2) "‰‹œsin 1 œ1 Ê converges nÄ_ # n nÄ_ # n # 44. lim n1 cos(n1)œ lim (n1)((cid:1)1)n does not exist Ê diverges nÄ_ nÄ_ 45. lim sin n œ0 because (cid:1)" Ÿ sin n Ÿ " Ê converges by the Sandwich Theorem for sequences nÄ_ n n n n # # 46. lim sin n œ0 because 0Ÿ sin n Ÿ " Ê converges by the Sandwich Theorem for sequences nÄ_ #n #n #n 47. lim n œ lim " œ0 Ê converges (using l'Ho^pital's rule) nÄ_ #n nÄ_ #n ln 2 Copyright © 2010 Pearson Education Inc. 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Section 10.1 Sequences 571 # $ 48. lim 3n$ œ lim 3n ln# 3 œ lim 3n(ln 3) œ lim 3n(ln 3) œ_ Ê diverges (using l'Ho^pital's rule) nÄ_ n nÄ_ 3n nÄ_ 6n nÄ_ 6 " 49. n lÄim_ ln(Èn(cid:2)n") œn lÄim_ Šˆn#È(cid:0)"1‹‰ œn lÄim_ n2È(cid:2)n1 œn lÄim_ 1Š(cid:2)È2Šn"‹‹ œ0 Ê converges n n " ˆ ‰ 50. lim ln n œ lim n œ1 Ê converges nÄ_ ln 2n nÄ_ ˆ2‰ 2n Î 51. lim 81n œ1 Ê converges (Theorem 5, #3) nÄ_ Î 52. lim (0.03)1n œ1 Ê converges (Theorem 5, #3) nÄ_ 53. lim ˆ1(cid:2) 7‰n œe( Ê converges (Theorem 5, #5) nÄ_ n 54. lim ˆ1(cid:1) "‰n œ lim ’1(cid:2) ((cid:1)")“n œe(cid:1)" Ê converges (Theorem 5, #5) nÄ_ n nÄ_ n 55. lim Èn 10nœ lim 101În†n1În œ1†1œ1 Ê converges (Theorem 5, #3 and #2) nÄ_ nÄ_ 56. lim Èn n# œ lim ˆÈn n‰# œ1# œ1 Ê converges (Theorem 5, #2) nÄ_ nÄ_ Î 57. lim ˆ3‰1În œ n lÄim_ 31În œ " œ1 Ê converges (Theorem 5, #3 and #2) nÄ_ n lÄim_ n1n 1 n 58. lim (n(cid:2)4)1ÎÐn(cid:2)4Ñ œ lim x1Îx œ1 Ê converges; (let xœn(cid:2)4, then use Theorem 5, #2) nÄ_ xÄ_ 59. lim ln În œ n lÄim_ ln În œ _ œ_ Ê diverges (Theorem 5, #2) nÄ_ n1n lÄim_ n1n 1 n 60. lim cln n(cid:1)ln(n(cid:2)1)dœ lim lnˆ n ‰œlnŠ lim n ‹œln 1œ0 Ê converges nÄ_ nÄ_ n(cid:2)1 nÄ_ n(cid:2)1 61. lim Èn 4nnœ lim 4Èn nœ4†1œ4 Ê converges (Theorem 5, #2) nÄ_ nÄ_ 62. lim Èn 32n(cid:2)1 œ lim 32(cid:2)a1Înb œ lim 3#†31În œ9†1œ9 Ê converges (Theorem 5, #3) nÄ_ nÄ_ nÄ_ 63. lim n! œ lim "†2†3â(n(cid:1)1)(n) Ÿ lim ˆ"‰œ0 and n! 0 Ê lim n! œ0 Êconverges nÄ_ nn nÄ_ n†n†nân†n nÄ_ n nn nÄ_ nn 64. lim ((cid:1)4)n œ0 Ê converges (Theorem 5, #6) nÄ_ n! 65. lim n! œ lim "' œ_ Ê diverges (Theorem 5, #6) nÄ_ 106n nÄ_ Š(10)n‹ n! 66. lim n! œ lim " œ_ Ê diverges (Theorem 5, #6) nÄ_ 2n3n nÄ_ ˆ6n‰ n! 67. lim ˆ"‰1ÎÐlnnÑ œ lim expˆ " lnˆ"‰‰œ lim expˆln 1(cid:1)ln n‰œe(cid:1)" Ê converges nÄ_ n nÄ_ ln n n nÄ_ ln n Copyright © 2010 Pearson Education Inc. Publishing as Addison-Wesley. 572 Chapter 10 Infinite Sequences and Series 68. lim lnˆ1(cid:2) "‰n œlnŠ lim ˆ1(cid:2) "‰n‹œln eœ1 Ê converges (Theorem 5, #5) nÄ_ n nÄ_ n 69. lim ˆ3n(cid:2)"‰n œ lim expˆn lnˆ3n(cid:2)"‰‰œ lim expŠln(3n(cid:2)1)(cid:1)"ln(3n(cid:1)1)‹ nÄ_ 3n(cid:1)1 nÄ_ 3n(cid:1)1 nÄ_ n œn lÄim_ exp(cid:1)3n3(cid:0)Š1(cid:2)(cid:2)"#3‹n3(cid:1)1(cid:2)œn lÄim_ expŠ(3n(cid:2)16)n(#3n(cid:1)1)‹œexpˆ69‰œe#Î$ Ê converges n " " 70. n lÄim_ ˆn(cid:2)n1‰n œn lÄim_ expˆn lnˆn(cid:2)n1‰‰œn lÄim_ expŠln n(cid:1)ˆln"‰(n(cid:2)1)‹œn lÄim_ exp(cid:1)nŠ(cid:2)(cid:2)n"#(cid:0)‹1(cid:2) n n # œ lim expŠ(cid:1) n ‹œe(cid:1)" Ê converges nÄ_ n(n(cid:2)1) 71. lim ˆ xn ‰1În œ lim xˆ " ‰1În œx lim expˆ" lnˆ " ‰‰œx lim expŠ(cid:1)ln(2n(cid:2)1)‹ nÄ_ 2n(cid:2)1 nÄ_ #n(cid:2)1 nÄ_ n #n(cid:2)1 nÄ_ n œx lim expˆ (cid:1)2 ‰œxe! œx, x(cid:4)0 Ê converges nÄ_ 2n(cid:2)1 " " lnŠ1(cid:2) #‹ Š2$‹‚Š1(cid:2) #‹ 72. n lÄim_ ˆ1(cid:1) n"#‰n œn lÄim_ expˆn lnˆ1(cid:1) n"#‰‰œn lÄim_ exp(cid:1) ˆ"‰n (cid:2)œn lÄim_ exp– n Š(cid:2) "#‹n — n n œ lim expˆ (cid:1)#2n ‰œe! œ1 Ê converges nÄ_ n (cid:1)1 73. lim 3(cid:0)n†6n œ lim 36n œ0 Ê converges (Theorem 5, #6) nÄ_ 2 n†n! nÄ_ n! 74. lim ˆ1101‰n œ lim ˆ1121‰nˆ1101‰n œ lim ˆ112201‰n œ0 Ê converges nÄ_ ˆ9‰n(cid:2)ˆ11‰n nÄ_ ˆ12‰nˆ9‰n(cid:2)ˆ12‰nˆ11‰n nÄ_ ˆ108‰n(cid:2)1 10 12 11 10 11 12 110 (Theorem 5, #4) (cid:0) 75. lim tanh nœ lim en(cid:1)e(cid:0)n œ lim e2n(cid:1)" œ lim 2e2n œ lim "œ1 Ê converges nÄ_ nÄ_ en(cid:2)e n nÄ_ e2n(cid:2)1 nÄ_ 2e2n nÄ_ 76. lim sinh(ln n)œ lim elnn(cid:1)e(cid:0)lnn œ lim n(cid:1)ˆn"‰ œ_ Ê diverges nÄ_ nÄ_ 2 nÄ_ # 77. n lÄim_ n#2 snin(cid:1)ˆ1n"‰ œn lÄim_ Šs2in(cid:2)ˆ"n"#‰‹ œn lÄim_ (cid:2)ˆŠc(cid:2)os2ˆ#"n(cid:1)‰‰2Š$‹n"#‹ œn lÄim_ (cid:2)(cid:2)#co(cid:1)sˆˆ2n"‰‰ œ #" Ê converges n n n n n 78. n lÄim_ nˆ1(cid:1)cos "n‰œn lÄim_ ˆ"(cid:2)ˆc"o‰s "n‰ œn lÄim_ (cid:1)sinˆŠ"n‰"#‘‹Šn"#‹ œn lÄim_ sinˆ"n‰œ0 Ê converges n n 79. lim ÈnsinŠ 1 ‹œ lim sinŠÈ1n‹ œ lim cosŠÈ1n‹Š(cid:1)2n31Î2‹ œ lim cosŠ 1 ‹œcos0œ1Êconverges nÄ_ Èn nÄ_ È1 nÄ_ (cid:1) 1Î nÄ_ Èn n 2n32 80. lim a3n(cid:2)5nb1În œ lim exp’lna3n(cid:2)5nb1În“œ lim exp’lna3n(cid:2)5nb“œ lim exp–3nln33n(cid:0)(cid:0)55nnln5— nÄ_ nÄ_ nÄ_ n nÄ_ 1 œ lim exp’Š35nn‹ln3(cid:2)ln5“œ lim exp’ˆ35‰nln3(cid:2)ln5“œexpaln5bœ5 nÄ_ ˆ35nn‰(cid:2)1 nÄ_ ˆ35‰n(cid:2)1 81. lim tan(cid:1)"nœ 1 Ê converges 82. lim " tan(cid:1)"nœ0† 1 œ0 Ê converges nÄ_ # nÄ_ Èn # Copyright © 2010 Pearson Education Inc. 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