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National and Regional Contests
France Contests
French Mathematical Olympiad
1988 French Mathematical Olympiad
Problem 2
Problem 2
Part of
1988 French Mathematical Olympiad
Problems
(1)
on n^6+5n^5*sin(n)+1
Source: France 1988 P2
5/18/2021
For each
n
∈
N
n\in\mathbb N
n
∈
N
, determine the sign of
n
6
+
5
n
5
sin
n
+
1
n^6+5n^5\sin n+1
n
6
+
5
n
5
sin
n
+
1
. For which
n
∈
N
n\in\mathbb N
n
∈
N
does it hold that
n
2
+
5
n
cos
n
+
1
n
6
+
5
n
5
sin
n
+
1
≥
1
0
−
4
\frac{n^2+5n\cos n+1}{n^6+5n^5\sin n+1}\ge10^{-4}
n
6
+
5
n
5
s
i
n
n
+
1
n
2
+
5
n
c
o
s
n
+
1
≥
1
0
−
4
.
algebra