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Moldova Contests
Moldova Team Selection Test
2019 Moldova Team Selection Test
2
2
Part of
2019 Moldova Team Selection Test
Problems
(1)
Ez pz trig
Source: Moldova TST 2019
3/8/2019
Prove that
E
n
=
arccos
n
−
1
n
arccot
2
n
−
1
E_n=\frac{\arccos {\frac{n-1}{n}} } {\text{arccot} {\sqrt{2n-1} }}
E
n
=
arccot
2
n
−
1
a
r
c
c
o
s
n
n
−
1
is a natural number for any natural number
n
n
n
. (A natural number is a positive integer)
trigonometry
TST
easy
geometry