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Moscow Mathematical Olympiad
1953 Moscow Mathematical Olympiad
257
257
Part of
1953 Moscow Mathematical Olympiad
Problems
(1)
MMO 257 Moscow MO 1953 x_n=(x^2_{n-1}+2)/(2x_(n-1))
Source:
8/9/2019
Let
x
0
=
1
0
9
x_0 = 10^9
x
0
=
1
0
9
,
x
n
=
x
n
−
1
2
+
2
2
x
n
−
1
x_n = \frac{x^2_{n-1}+2}{2x_{n-1}}
x
n
=
2
x
n
−
1
x
n
−
1
2
+
2
for
n
>
0
n > 0
n
>
0
. Prove that
0
<
x
36
−
2
<
1
0
−
9
0 < x_{36} - \sqrt2 < 10^{-9}
0
<
x
36
−
2
<
1
0
−
9
.
recurrence relation
Sequence
inequalities
algebra