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12
G 12
G 12
Source:
May 25, 2007
trigonometry
number theory
relatively prime
Irrational numbers
Problem Statement
An integer-sided triangle has angles
p
θ
p\theta
pθ
and
q
θ
q\theta
qθ
, where
p
p
p
and
q
q
q
are relatively prime integers. Prove that
cos
θ
\cos\theta
cos
θ
is irrational.
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