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Putnam
1970 Putnam
A1
Putnam 1970 A1
Putnam 1970 A1
Source: Putnam 1970
May 17, 2022
Putnam
function
trigonometry
power series
Problem Statement
Show that the power series for the function
e
a
x
cos
b
x
,
e^{ax} \cos bx,
e
a
x
cos
b
x
,
where
a
,
b
>
0
a,b >0
a
,
b
>
0
, has either no zero coefficients or infinitely many zero coefficients.
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