TÍNH TỔNG 20180 12018 20182 ... 20182017 20182018.T = − + − − +3 4 5...

1

.

k

k

1

k

k

k

1

k

=

=

0

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k

k

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Do đó

1

2

( )

018

1 2018

2018

2

( )

=

1

k

k

1

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k

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=

+

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1

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1

∑ ∑ ∑

C

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k

k

k

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1

2018

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2018

3

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1

2018

( )

2018

2018

2018

3

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=

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k

k

k

Đặt

1

− =

x

t

thì

1

0

1

2021

2020

2019

t

t

t

( ) ( ) ( ) ( )

1

∫ ∫ ∫

018

2

=

=

− +

=

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2

2018

2

2018

x

x

2

dx

t

t

dt

t

t

t

dt

1

1

.

.

2

1

2.

2021

2020

2019

0

1

0

0

+