Đ THI HSG HUYN BNH XUYÊN - VNH PHC - NĂM HC 2008-2009
Bi 1
   
   
      
−
− =
− − +
Bi 2!"#$%&'()*+( *

,*

(*,(,-
Bi 3.$&/0"'
  1
*  * * *   * − + + + + = + −
Bi 423456/789':;<=
·
;4 = α
>?@

.ABCDED/FD=G
HI2;3<=;4.AJ.<=KDED/FD=AHI2;33;<=2;4
3L2B94C:M
 J.NN2<=
J. 2
JK 34
=
 MC2>
 OKJ. OBMC
Bi 5P/06Q'R

− − − − − + − − −
− = = = =
− − − − − − + − + +
− − + − + − − − − − −
= = = =
− + + − + − + + + +

Bi 2!"#$%&'()*+( *

T*

(*T(T-
.$
!5 ⇔(*

 *

*T-⇔
 
  
* * - * * * - * -
( *
*  *  * 
+ − + + − −
= = = +
+ + +
U"(∈V)*T-*

⇔*T- *- *


* -
=

 
+ = =


 
= = −

+ = ⇔ = ⇔ ⇔

 

=
=


 
+ = =

 
= −

!(<=&/0"
UY*Z
UY*T⇒(T
UY*-⇒(-
UY*T-Z
U[(*+( ∈\T+T +-+- ]




=
+ + =


+ + + − =


U[(&/0"65^RP'(#D=*
Bi 423456/789':;<=
·
;4 = α
>?@

.ABCDED/FD=G
HI2;3<=;4.AJ.<=KDED/FD=AHI2;33;<=2;4
3L2B94C:M
 J.NN2<=
J. 2
JK 34
=
 MC2>
 OKJ. OBMC
.$
 O3_`5
3J 3. 
3_ 3` 
= =

MB 34
=
%c&E 
J. 2
JK 34
=
'(
MC J.
MB JK
=
f:5
·
·
.JK ;4=
>5A5%&:/0
465
·
·
BMC .JK= = α
U[(OK.J OBMC
Bi 5P/06Q'R
  
   
      
+ + ≥
+ + +
.$ !5
 
 
   

+ +
+ + ≥ + + −
+ + +
_%

X ⇔X⇔T XT
U[(
  
    

       
+ + ≥ − =
+ + +
4#'kl*$(⇔
α
α
α
α
f
M
K
J
.
C
B
e
`
_
d
;