Đ THI HSG HUYN BNH XUYÊN - VNH PHC - NĂM HC 2008-2009
Bi 1
−
− =
− − +
Bi 2!"#$%&'()*+( *
,*
(*,(,-
Bi 3.$&/0"'
1
* * * * * − + + + + = + −
Bi 423456/789':;<=
·
;4 = α
>?@
.ABCDED/FD=G
HI2;3<=;4.AJ.<=KDED/FD=AHI2;33;<=2;4
3L2B94C:M
J.NN2<=
J. 2
JK 34
=
MC2>
OKJ. OBMC
Bi 5P/06Q'R
+ + ≥
+ + +
HƯ%NG D'N GI(I
Bi 1
−
− =
− − +
.$
!S⇔
⇔
T
!5
1 1 1 1
− − − − − + − − −
− = = = =
− − − − − − + − + +
− − + − + − − − − − −
= = = =
− + + − + − + + + +
Bi 2!"#$%&'()*+( *
T*
(*T(T-
.$
!5 ⇔(*
*
*T-⇔
* * - * * * - * -
( *
* * *
+ − + + − −
= = = +
+ + +
U"(∈V)*T-*
⇔*T- *- *
⇔*
T-*
⇔*
TW*
⇔W*
U"*∈V<=*
X)W*
⇔
*
* *
* *
* @ *
* -
* -
* W * -
* -
=
+ = =
= = −
+ = ⇔ = ⇔ ⇔
=
=
+ = =
= −
!(<=&/0"
UY*Z
UY*T⇒(T
UY*-⇒(-
UY*T-Z
U[(*+( ∈\T+T +-+- ]
Bi 3.$&/0"'
1
* * * * * − + + + + = + −
.$6Q'R*X
1
* * * * *
* * * * * *
* * * *
* * *
* *
*
*
*
** *
* * *
− + + + + = + −
⇔ − + + + − + − + − =
⇔ − − − + + − − =
⇔ − − + + − =
− − = − =
=
⇔ ⇔ ⇔ ⇔ =
=
+ + =
+ + + − =
U[(&/0"65^RP'(#D=*
Bi 423456/789':;<=
·
;4 = α
>?@
.ABCDED/FD=G
HI2;3<=;4.AJ.<=KDED/FD=AHI2;33;<=2;4
3L2B94C:M
J.NN2<=
J. 2
JK 34
=
MC2>
OKJ. OBMC
.$
O3_`5
3J 3.
3_ 3`
= =
⇒J.NN26aDb!Dc6$
!SJ.NN_`⇒
J. J. J.
_` 2
2
= = ⇒ =
!/0G<Y2de
JK
34
=
'(
J. JK J. 2
2 34 JK 34
= ⇒ =
!5
·
·
2M4 ;4= = α
5A5:/0<'Z5
.AfD=6gIMC<=2!5
·
·
MC 2M4= = α
Dc
!5MCMffC2f>f>2ff >2>
/0G&E 5MB34>
!S65'(
MC 2
MB 34
=
%c&E
J. 2
JK 34
=
'(
MC J.
MB JK
=
f:5
·
·
.JK ;4=
>5A5%&:/0
465
·
·
BMC .JK= = α
U[(OK.J OBMC
Bi 5P/06Q'R
+ + ≥
+ + +
.$ !5
= − ≥ − = −
+ +
h&Pi#6j*
(
X*(
!/0G
= − ≥ −
+ +
<=
= − ≥ −
+ +
465
+ +
+ + ≥ + + −
+ + +
_%
X ⇔X⇔T XT
U[(
+ + ≥ − =
+ + +
4#'kl*$(⇔
α
α
α
α
f
M
K
J
.
C
B
e
`
_
d
;
2
4
3