Mathematics HL - OPTION 9 Calculus

2012·18.49 MB·english

by  Paul Fannon

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Level
Mathematics
Higher
-
9
Option:
Topic
Calculus
for the IB
Diploma
Vesna
Paul Fannon, Kadelburg,
Ben Woolley and Stephen Ward
CAMBRIDGE UNIVERSITY PRESS
Cambridge, New York, Melbourne, Madrid, Cape Town,
Sao
Singapore, Paulo, Delhi, Mexico City
Cambridge Press
University
CB2
The Edinburgh Building, Cambridge 8RU, UK
www.cambridge.org
Information on this title: www.cambridge.org/9781107632899
\302\C25a1mbridge University Press 2013
This publication is in copyright. Subject to statutory exception
and to the provisionsofrelevant collective licensing agreements,
no reproduction ofany part may take place without the written
permission ofCambridgeUniversity Press.
First published 2013
Printed in Poland by Opolgraf
Acataloguerecordfor this publication isavailablefrom the British Library
ISBN 978-1-107-63289-9 Paperback
Cover
Thinkstock
image:
Cambridge University Press has no responsibility for the persistence or
accuracyofURLs for external or third-party internet websites referred to in
this publication, and doesnot guarantee that any content on such websitesis,
orwill remain, accurate or appropriate. Information regarding prices,travel
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the time of first printing but Cambridge University Press doesnotguarantee
theaccuracyof such information thereafter.
NOTICETO
TEACHERS
Worksheets and copies ofthem remain in the copyright ofCambridgeUniversity Press
and such copies may not be distributed or used in any way outside the
purchasing institution.
'a
Contents
How to use this book
IV
Introduction
1
1 Limits of sequences and functions 3
4
IThe limit of a sequence
1\302\2T43hBe Squeeze Theorem 8
11
IThe limit of a function
19
Hi L'Hopital's Rule
IContinuous functions 24
IDifferentiate functions 29
IRolle's Theorem and the MeanValue Theorem 34
45
Improper integrals
The Fundamental Theorem of Calculus 46
Convergent and divergent improper 50
integrals
57
Approximation of improper integrals
Infinite series 65
66
Convergence of series
H Testsfor convergenceand divergence 69
88
Power series
4 Maclaurin and Taylor series 99
99
-rA^ Maclaurin series
104
Approximations to the Maclaurin series
110
Maclaurin series ofcompositefunctions
113
Taylor series
Applications 117
Differential equations 123
ISetting up differential equations 123
ISeparation of variables 126
IHomogeneous differential equations 129
HI Linear differential equations 132
136
IApproximations to solutions
6 Summary and mixed examination practice 149
Answers 162
Glossary 174
178
Index
180
Acknowledgements
Contents in
c XJ^\\ + d.
How to use this book
Structure of the book
Thisbookcoversallthemateriaflor Topic 9 (Calculus Option) of the HigherLevel Mathematics
syllabus for the International Baccalaureate course.Itassumesfamiliarity with the core material
(syllabus topics 1to6),particularly Calculus (syllabus topic 6) and Sequences andSeries(syllabus
topic 1.1). We have tried to includeinthemaintextonly the material that will be examinable.
Therearemany interesting applications and ideas that go beyond thesyllabus and we have tried to
highlight someofthesein the 'From another perspective' and 'Research explorer'boxes.
The five main chapters are probably best coveredintheorderpresented, although chapter 5 (except
for the lastsection)only requires knowledge of the core calculus material.Chapter6contains a
summary of all the topics andfurtherexaminationpracticew,ith many of the questions mixing
severaltopics- afavourite trick in IB examinations.
Each chapter startswith a list of learning objectives to give you an idea about what the chapter
contains.Thereisan introductory problem at the start ofthetopicthat illustrates what you should
be ableto doafter you have completed the topic. You should notexpecttobeable to solve the
problem at the start, butyou may want to think about possible strategiesandwhat sort of new facts
and methods wouldhelpyou. The solution to the introductory problem isprovidedat the end of
6.
chapter
boxes
Key point
The most important ideas and formulae are emphasisedinthe'KEY POINT' boxes. When the
formulae are given in theFormulabookletth,ere will be an icon: ;ifthis iconisnotpresentth,en
the formulae are not in the Formula bookletandyou may need to learn them or at least know how
to derive them.
Worked examples
Eachworkedexampliessplitinto two columns. On the right iswhat youshouldwrite down.
Sometimes the example might include moredetailthenyou strictly need, but it is designed to give
you an idea of what isrequiredtoscorefull method marks in examinations. However, mathematics
isaboutmuchmorethan examinations and remembering methods. So, on theleft of the worked
examples are notes that describe the thought processes and suggestwhichrouteyou should use to
tackle the question. We hope that these will help you with any exercisequestionsthat differ from
the worked examples. It isvery deliberatethat some of the questions require you to domorethan
the methods in the worked examples.Mathematicsisaboutthinking!
repeat
How to use this book
Signposts
There areseveralboxesthat appear throughout the book.
Theory of knowledge issues
Every lesson is a Theory of knowledge lesson,butsometimesthelinks may
not be obvious. Mathematics isfrequentlyusedasan example of certainty and
truth, but this isoften not the case. In these boxes wewill try to highlight some X
of the weaknessesandambiguitiesin mathematics as well as showing how
mathematicslinkstootherareasof
knowledge.
From another perspective
The International Baccalaureate\302\256 encourages looking at things in different ways.
Aswellashighlightingsomeinternational differences between mathematicians
these boxes alsolookat other perspectives on the mathematics wearecovering:
historical,
and cultural.
pragmatic
Research explorer
As part ofyourcourse, will be asked to write areportonamathematical
you
topicofyour choice. It is sometimes difficult to knowwhichtopicsaresuitable
as a basis for such reports, andsowe have tried to show where atopiccanact
as a jumping-off point for further work. Thiscanalsogive you ideas for an
Extended essay.Thereisalotofgreatmathematicoust there!
Exam hint
Although we would encourage to think of mathematics as more than just
you
learningin order to pass an examination, there aresomecommonerrors it is
useful for you to beawareof.Ifthereisacommonpitfall we will try to highlight
it in these boxes.
Fast forward / rewind
Mathematics is all about making links. You might beinterestedtoseehow something you
have just learned will be usedelsewherein the course, or you may need to gobackand
remind yourself of a previous topic. Theseboxesindicateconnectionwsith other sections
of the book to helpyou find your way around.
How to use the questions
The colour-coding
The questions are colour-coded to distinguish between thelevels.
Blackquestions are drill questions. They help you practisethemethodsdescribedinthe book, but
they are usually not structuredlikethequestions in the examination. This does not meanthey are
some of them are quitetough.
easy,
How to use this book
Ai
i ***\\ + 0,.
Each differently numbered drill question tests a different skill.Letteredsubparts of a question
are of increasing Within each lettered part there may bemultipleroman-numeraplarts
difficulty.
((i), (ii),.-) >all of which are of asimilardifficulty. Unless you want to do lots ofpracticewewould
recommendthat you only do one roman-numeral part andthencheckyour answer. If you have
made amistakethenyou may want to think about what wentwrongbeforeyou try any more.
Otherwise move on to thenextlettered
part.
Green questions are examination-style questions which shouldbeaccessiblteostudents on
the path to getting agrade3or4.
Blue questions are harder examination-style questions. Ifyou areaimingfor a grade 5 or 6you
shouldbeabletomake most of these.
significant progress through
Red questionsareat the very top end of difficulty in the examinations.Ifyou can do these
then you arelikelytobeoncoursefor a grade 7.
Gold questions are a type that are not setintheexaminationbut, are designed to provoke
\342\226\241thinking and discussioninordertohelpyou to a better understanding of aparticular
concept.
At the end of each chapter you willseelongerquestions typical of the second section of
InternationalBaccalaureate\302\256 examinations. These follow the same colour-coding scheme.
Ofcourse,theseare just guidelines. If you are aiming for a grade 6, do not be surprisedifyou find
a green question you cannot do.Peoplearenever equally good at all areas ofthesyllabus. Equally,
if you can do alltheredquestions that does not guarantee you will getagrade7;after all, in the
examination you haveto dealwith time pressure and examination stress!
Thesequestionsaregradedrelative to our experience of the finalexamination,sowhen you first
start the course you willfind allthequestionsrelatively hard, but by the end ofthecoursethey
should seem more straightforward. Do not getintimidated!
We hope you find the Calculus Option an interestingandenrichingcourseY.ou might also find
it quite challenging, butdonotgetintimidatedf,requently topics only make sense after lots of
revisionandpractice.Perseveraend you will succeed.
The author team.
Howto use this book
Introduction
In this Option you will learn:
\342\2h0o0w\242 to find a limit of a sequence (thevaluethat the terms of the sequence approach)
\342\2a0b0o\u24t2 various methods for finding limits of functions, including L'Hopital's Rule
\342\2fo00rm\24a2l definitions of continuity and differentiability of functions,and someuseful
of differentiable functions
properties
\342\2h0o0w\242 we can extend definite integration to allow one ofthelimits to tend to infinity
\342\2h0o0w\242 to decide whether infinite series have a limit
\342\2h0o0w\242 to use series to approximate various functions(MaclaurinandTaylor series)
\342\2h0o0w\242 to solve certain types of differential equations,both exactly and approximately.
Introductory problem
Consider aweddingcakewith four layers:
Each layer has at1hic1knessof1.The first layer has a radius of 1,theseconda radius of\342\200\2t2h4e,
2
third a radius of- and the fourth a radius of\342\200\224.
3 4
Find the volume ofthecakeand the surface area (excluding the bottom ofthefirst layer) that
needs covering with icing.
Now imaginethereareinfinitely many layers to the cake. What canyousay about the volume
of the cakeandthesurfaceareathat needs icing now?
Introduction
fit
C XJ^\\ + d.
The calculus option buildson different areas of the course, using thetheoryoffunctions,
many
sequenceansd series, differentiation and integration. Some oftheideasyou will study here have
interested many ofthegreatestmindsin mathematics: Euler, Newton, Leibniz, Cauchy, Riemann
andothers;and have far reaching applications both within mathematics andothersubjectssuch as
physics and engineering.
The option issplitintofive chapters:
1 Limits of sequences andfunctionslooksfirst at the behaviour of sequences aswetakemoreand
more terms. How can we determine whichsequencesheadtowards (converge to) a finite value
when wetakeinfinitely many terms, and which just become infinitely large? We then examine the
values offunctionsaswegetcloserand closer to a particular value in their domain.Thefocusis
particularly on quotients where both the numerator anddenominatoraretending to 0 or where
they arebothtendingto\302\25B1uo.ilding on the idea of alimit ofafunction,wethenlookat where
functions are continuous and where theycanbedifferentiated, before considering two important
theorems for differentiable functions.
2Impropeinrtegrals looks at what happens when wetaketheupperlimitonan integral to
be oo.Will this alwaysgive an infinite value for the integral (andhencean infinite area under the
curve), or aretheresomecircumstances in which that value (or area) isfinite? And again how do
we know whichisthecasefor a given integral? This chapter starts with alookat the Fundamental
Theorem of Calculus.
3Infinite series builds on both the previous chaptersandexaminesthesumsofinfinitely many
terms. We have already seen with somegeometricseriesthat it is possible to add together infinitely
many terms and yet get afinite value for the sum to infinity; here we look at awide rangeof
different series and develop ways to test iftheseriesconverges (has a finite value) or not. We also
link improper integrals and infinite sumsandlookat ways of placing bounds on the value of an
infinite sum.
4Maclaurin and Taylor series establishes a way of representing many familiar functions as infinite
series in increasing integer powersofx.We examine polynomial approximations for functions, and
theiraccuracy,andusetheseriesrepresentation of functions for integration and to calculatelimits,
againparticularly those where both numerator and denominator aretendingto0or<*>.
5 Differential equations looks at setting upandsolvingdifferential equations, which are used
to describe thebehaviourofmany processes in nature and engineering. We look atthree
methodsforsolving different types of these equations and then considersomemethods to find
approximate solutions to differential equationsthat aredifficult (if not impossible) to solve in the
standard
way.
Introduction
* - **\\