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Putnam
1982 Putnam
A5
A5
Part of
1982 Putnam
Problems
(1)
about four integers
Source:
5/12/2010
a
,
b
,
c
,
d
a, b, c, d
a
,
b
,
c
,
d
are positive integers, and
r
=
1
−
a
b
−
c
d
r=1-\frac{a}{b}-\frac{c}{d}
r
=
1
−
b
a
−
d
c
.And,
a
+
c
≤
1982
,
r
≥
0
a+c \le 1982, r \ge 0
a
+
c
≤
1982
,
r
≥
0
. Prove that
r
>
1
198
3
3
r>\frac{1}{1983^3}
r
>
198
3
3
1
.
Putnam
number theory unsolved
number theory