... n fans. How many
ways h(n, k) are there for exactly k fans to get their own hats back?
For example, if n = 4 and if the hats and fans are named A, B, C, D,
the
4!
= 24 possible ways for hats ... land generate the following numbers of
rightful owners:
ABCD 4 BACD 2 CABD
1
DABC
0
ABDC 2 BADC
0
CADB
0
DACB
1
ACBD 2 BCAD
1
CBAD 2 DBAC
1
ACDB
1
BCDA
0
CBDA
1
DBCA 2
ADBC
1
BDAC
0
CDA...
... intended as an
antidote to “Abstract Mathematics, ” since concrete classical results were rap-
idly being swept out of the modern mathematical curriculum by a new wave
of abstract ideas popularly called ... hard one to the easy one.
time
to
do
warmup
Let’s apply these ideas to a useful example. Consider the array
exercises 4 and 6.)
(Or to check out
al
al
al
a2
the Snickers ba...
... name and
conquer.
a = ~ap’J , a- ’ =
a+ a’;
The change of
vari-
able from k to j is
b = [va-‘l ,
va-’ = b -v’.
Thus a = {a ‘} is the fractional part of a- ‘, and v’ is the mumble-fractional
part ... notations for rising powers as well as falling powers.
Mathematicians have long had both sine and cosine, tangent and cotangent,
secant and cosecant, max and min; now we also have both f...
... depth. It is easily
proved by induction; we have, for example,
K(ao,al,az ,a3 +l /a4 )
:=
K(ao,al ,a2 ,a3 ,a4 )
K(al, az,
a3
+ l /a4 1
K(al,az,as,ad)
’
because of the identity
K,(xl,.
. .
,xn-lrxn+Y)
= ... continued fraction can also be obtained directly: Let
CQ
= a and
for k 3 0 let
ak
=
Lakj
;
1
ak
=
ak+
Kkfl
(6. 142 )
The a s are called the “partial quotients” of...
... sequences
(al ,a2
. , al,,) of
+1's
and
-1's
have the property that
al
+ a2
+.
. . +
azn =
0
and have all their partial sums
al,
al
+a2 ,
. . . .
al
+a2 + +aZn
nonnegative? There ...
&
z
0.268. This needs to be taken into account if we
try to use formula (7.38) in numerical calculations. For example, a fairly
expensive name-brand hand
Icalculator
comes...
... month each person is reassigned
to an adjacent state, each adjacent state being equally likely. (Here’s a
diagram of the adjacencies:
The initial states are circled.) For example, Alice is restationed ... (8.82) that A
would probably beat B, that B would probably beat C, and that C would
probably beat A; but all three patterns are simultaneously in the game.)
What are each player’s cha...
... “Eulerian” (eighteenth-century) mathematics.
9.3 0 MANIPULATION 44 7
This may look worse than the sum we began with, but it’s actually a step for-
ward, because we have very good approximations for ...
E
S.)
44 4 ASYMPTOTICS
Problem 4: A sum from an old final exam.
When Concrete Mathematics was first taught at Stanford University dur-
ing the 1970-1971 term, students were a...
... results
about Fermat’s
Last Theorem; see
Ribenboim j 249 j.j
A ANSWERS TO EXERCISES 527
If the harmonic
aa
and a
bb.
Thus each bb behaves like a drone in the bee tree and each
aa
behaves like a queen, ... thereby
eliminating an upper parameter and a lower parameter. Thus, for example,
we get closed forms for F( a, b; a
-
1; z), F(
a, b; a
-
2; z), etc.
Gauss
[116...
... Write Mathematics,
American Mathematical Society, 1973, 19 -48 .
142 Paul R. Halmos,
I
Want to Be a Mathematician: An Automathography.
v.
Springer-Verlag, 1985. Reprinted by Mathematical Association ... lat- 347
erum in polygona m laterum, per diagonales resolvi quzat,” Nova acta
academia: scientiarum Petropolitana: 9 (1791), 243 -251.
110 Martin Gardner, “About phi, an irrational num...