Lê Thanh Bình - THPT Tĩn
h Gia 1
Lê Thanh Bình - THPT Tĩn
h Gia 1
( )
( ) ( )
( )
*,
1 2
1.2 2.3 1 1
3
   n
n n n
n n
∈
+ +
+ + + + =
¥
) 1.
)
 !"#
$ !"#%&'()
*  

+
"

a n
b
n
=

*
1.
!"#0
1.!"#0 2!"#3
, %
"#
56(/!"#0 +
0
,2

6 +


k
n
n
n k n k
=
+∈
∈
= =
¥
¥
( )
( )
.
*,
2)
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1 

1.2 2.3 1 1
3
   n
n n n
n n
∈
+ +
+ + + + =
¥
1, 2!"#;n
• =
( )
*<=6>!"#0 7 ? n k k=• ∈¥
( )
( ) ( )
( )
1 2
1.2 2.3 **. 1
3
k k k
k k
+
=
+
+ + + +
1!"#06@ 7?n k= +
( ) ( ) ( )
( ) ( ) ( )
1.2 2.3
1 2

3
2 11 2k kk k k
k k k
k
+ +
+ + ++ = + ++ + ++
( ) ( )
( ) ( ) ( )
1 2 3
1 2 1 .
33
k k k
k k
k
+ + +
 
= + + + =
 ÷
 
( )
*.,-!"#0 CD9=n ∈• ¥
( )
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5AE=*F&7&
=FG
4HDF.
 0
I6
A n n
∈

-
A n n
A n n k A n n
n n
k k
A
=
= = +
∈
∈
¥
¥
( )
2
*, 1 3 5 2 1K     n n n
∈ + + + + − =
¥
( )
( )
2
2
2 2 2
4 1
*, 1 3 5 2 1
3
N   
n n
n n
−
∈ + + + + − =

> ≥
5'8&F9()99IM9W
( ) ( )
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&F(HD
F. 0 
F9()99IM9

+
A n n n p p
∈ ∈≥
¥ ¥
Lê Thanh Bình - THPT Tĩn
h Gia 1
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0X
 0

( )
*, . 0  - A n n n p
∈ ≥
¥
Lê Thanh Bình - THPT Tĩn
h Gia 1
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1
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( ) ( )
*,
1 "
*
*, "
C
F9()99IM98HF()F=6
("
HDF. 0
 0
(K
P
4 0
A n n n p
A p
A k A k k k p
p
∈ ≥
⇒ + ∀ ∈ ≥
∈

= +
∈
¥
¥
*."#0  n
∈
¥
Lờ Thanh Bỡnh - THPT Tn
h Gia 1
Ôn lại lý thuyết, đọc tiếp phần còn lại của
bài 1 và làm các bài tập trang 100-101 SGK.
Lê Thanh Bình - THPT Tĩn
h Gia 1
( ) ( )
2
*,
1 3 5 2 1 1
  n
n n
∈
+ + + + − =
¥
1, 2!"#;n
• =
( )
*<=6>!"#0 7 ? n k k=• ∈¥
( ) ( )
2
1 3 5 2 1 *k k
+ + + + − =

( )
2
2
2 2
4 1
1 3 5 2 1 *
3
k k
k
−
+ + + + − =
1!"#06@ 7?n k= +
( ) ( )
( ) ( )
2
2 2
2 2
1 4 1 1
1 3 5 2 1 2 1
3
k k
k k
 
+ + −
 
+ + + + − + + =
<=
( )
( )
2

4 1
1 3 5 2 1 1
3
n n
n
−
+ + + + − =
( )
( ) ( )
2
2
3 2
1 4 1 1
1 4 8 3
4 12 11 3
3 3 3
k k
k k k
k k k
 
+ + −
 
+ + +
+ + +
   
= = =
Re
Re