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2019 BMT Spring
8
2019 BMT Individual 8
2019 BMT Individual 8
Source:
January 9, 2022
algebra
Problem Statement
Let
ϕ
=
1
2019
\phi =\frac{1}{2019}
ϕ
=
2019
1
. Define
g
n
=
{
0
if
r
o
u
n
d
(
n
ϕ
)
=
r
o
u
n
d
(
(
n
−
1
)
ϕ
)
1
otherwise
.
.
g_n =\begin{cases} 0 & \text{ if} \,\,\,\, round (n\phi) = round \,\,\,\, ((n - 1)\phi) \\ 1 & \text{ otherwise} .\end{cases}.
g
n
=
{
0
1
if
ro
u
n
d
(
n
ϕ
)
=
ro
u
n
d
((
n
−
1
)
ϕ
)
otherwise
.
.
where round
(
x
)
(x)
(
x
)
denotes the round function. Compute the expected value of
g
n
g_n
g
n
if
n
n
n
is an integer chosen from interval
[
1
,
201
9
2
]
[1, 2019^2]
[
1
,
201
9
2
]
.
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