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Putnam
1979 Putnam
B1
B1
Part of
1979 Putnam
Problems
(1)
Putnam 1979 B1
Source:
4/8/2022
Prove or disprove: there is at least one straight line normal to the graph of
y
=
cosh
x
y=\cosh x
y
=
cosh
x
at a point
(
a
,
cosh
a
)
(a,\cosh a)
(
a
,
cosh
a
)
and also normal to the graph of
y
=
y=
y
=
sinh
x
\sinh x
sinh
x
at a point
(
c
,
sinh
c
)
.
(c,\sinh c).
(
c
,
sinh
c
)
.
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