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CALCULUS
AN INTUITIVE AND PHYSICAL APPROACH
2ND ED
BY
Morris Kline
John Wiley & Sons, Inc,
NEW YORK • LONDON • SYDNEY • TORONTO
,This material may be reproduced for
testing or instructional purposes by
people using the text.
ISBN 0 471 02396 5
Printed in the United States of America
10 98765432
, Introduction
i
1. The Solutions In This Manual.
The solutions of all the exercises in the text are given in full.
The primary reason is to save professors' time. Choosing exercises for
homework assignments can be a laborious matter if one must solve fifteen,
twenty or more to determine which are most suitable for his class. A
glance at the solutions will expedite the choices.
The second reason is that in many institutions calculus is taught
by teaching assistants who have yet to acquire both the training and ex
perience in handling many of the mathematical and physical problems. The
availability of the solutions should help these teachers.
2. Suggestions For The Use Of The Text.
The one-volume format of this second edition should give profes
sors more latitude in the choice of topics which might be suitable to the
interests of the students or to the length of the course.
Several types of choices might be noted. Because precalculus
courses have become more common since the publication of the first edi
tion, some of the analytic geometry topics may no longer have to be
taught in the calculus course. The most elementary topics of analytics
have been put in an appendix to Chapter 3, Section 4 of Chapter 4, Sec
tion 5 of Chapter 7, and the Appendix to Chapter 7. If familiar to the
students, all or some can be omitted.
Though I believe strongly in the importance of physical and, more
generally, real applications to supply motivation and meaning to the
calculus, again class interests and available time must enter into de
termining how many of these applications can be taken up. I have there
fore starred all those sections and chapters which can be omitted without
disrupting the continuity.
The last chapter, which is intended as an introduction to the
theory or rigor, can be taken up at almost any point after Chapter 10.
However, I personally believe that the intuitive approach should be
maintained throughout and that this chapter should be left for the last
and then taken up only if time permits.
The complete text is intended for a three semester, three hours a
week course. However, in view of the number of sections and chapters
that are not essential to the continuity the text can be used for shorter
courses including those offered in the fourth high school year.
3. Some Additional Topics.
Some physical applications which were included in the first edi
tion were omitted inthe second one and replaced in the text proper by
applications to economics and to other social science areas. A few of
those omitted are reproduced here. They may be useful as suggestions
, 2
for additional work which bright or somewhat advanced students can under
take, as fill-ins for periods which for one reason or another cannot be
used for regular work, or as material for a mathematics club talk. Ex
ercises and solutions relevant to these additional topics are also in
cluded here.
A. The Hanging Chain.
In the text proper we derived the equation of the chain or cable
suspended from two points (Chap. 16, Sect. 4) on the assumption that the
weight per unit length of the cable is the same all along the cable.
However, the theory developed there can be used to solve more general
problems. One is to determine the shape of the cable if the weight per
unit length or, one can say, the density per unit length is specified.
The second is, given the desired shape of the cable, how can we fix the
distribution of the mass along the cable so that it assumes the desired
shape? Both of these problems are readily solved with the theory at hand.
The derivation of (21), the equation of the cable, in the text
proper, presupposed that the weight of the cable per unit foot is con
stant all along the cable. Let us now see what we can do when we let the
. weight of the cable vary from point to point. Let us denote by w(s) the
function that gives the weight per unit foot at point s. Then (11) and
(13) still hold, but (14) must be changed to read
(1) Ty = Jw(s)dx + D.
If we divide this equation by (11) and use the fact that T /Т is y', we
obtain Y
(2) У' = =r- Jw(s)ds + D’
x0
where D* is D/T_. If the function w(s) is given, we can calculate
/w(s)ds. The quantity D' can now be fixed by letting s be 0 at y' = 0.
We now have y' as a function of s. Next we may proceed as we did in the
case where w(s) is a constant and seek to obtain s as a function of x
through
but y' is now given by (2). If the integration can be performed and s is
obtained as a function of x, we can substitute this value of s in (2) and
attempt to obtain у as a function of x.
We can also solve the second problem. Suppose that we wish
to distribute weight along the cable so that the cable hangs in a given
shape; that is, we presume that we know the equation of the cable and we
wish to find w(s). To solve this problem, we differentiate (2) with
respect to x. On the left side differentiation with respect to x pro
duces y". On the right side to differentiate with respect to x we use
the chain rule and differentiate with respect to s and multiply by ds/dx.
The derivative of Jw(s)ds with respect to s must be w(s) because the
integral is that function whose derivative is w(s). Thus our result is