Đề thi HSG Toán 9 và ĐA tr NCTrứ

       ! ĐÊ ̀ DỰ TUYỂN THI HO ̣ C SINH GIO ̉ I CÂ ́ P HUYÊ ̣ N tháng 1/2010 "  #$%&'()*+,- ! .),)"  +)+)*+,/ 0 "( 12 $333$34 56 −+−−− 78 ! # $3 ≥ 9( 2 :::5;$;5;$;5;$;5;$; ++++ "  #5%&'(#" 0 #<)/8+=,>-  +) "( ?63365@3 6 5 =++++ 9( 533A&3A& 55 +−−=+ "  #6%&'(1B C ,=#" ! D'B ! .=#"E.)E6.B9" ! +)"  +=F*  +F/8 C ,F"  G  BGH;I" 0 +<)* 0 D  BG6;I" 0 +<)* 0 D  BG$;I" 0 +<)* 0 D #J  +K#J C +<)" 0 #9" ! +78 ! #=#" ! 9L  +=+)"M7"  IB ! ,#J  +DB#+=/8  #'ND7J  <)" 0 #9L  +=+)"M: E 0 #<)" 0 #9" ! +9L  +=." ! .)+"  EO "  #&%&'()E,"D=#" ! ..E ! 9"." C +)F"  "P9P.:<F"  +/ 0 ".)M7#.M 0 ","D=#" ! .:)/ ! += D#+)>L  +=,"FMB+.E !  <6.<9<"<< ≤−+−+−  "  #H%&'()E+/ 0 "'/8  +=,>E  +,*D%('/8  +=K- ! +)25P1F"  DB C ,'#J 0 DQ#'B C +=,>J+ 'E" C +PKN 0 17MB+==E ! .%,)MB C .+/ 0 "'/8  +=,>E  +%((E C #7"  RF*  +F/8 C ,F"  )-  +) .)#J ! ..M 0 "1,>J+P:E C #PSF*  +F/8 C ,F"  ,>M+='#J 0 D.M 0 "17"  1: "( )/ ! +=D#+):2R: 9( T" ! .'#+)7# C ,>- ! .M 0 "'#J 0 D1'J 0 Q#J C +,- ! .),/ ! =#" ! .RS'" C ,=#" ! ,># C F8 ! ++)* ! ,: HẾT $ ĐA ́ P A ́ N "  #$%&'( "( 12 $333$34 56 −+−−− 78 ! # $3 ≥ ($334%$3 −+−−= %;P5H'( ( & 5H & $ $3$3%$3 −+−−−−−= %;PH'(         −       −−−−= & 5H 5 $ $3$3 5 %;PH'( ( )( ) 5$36$3$3 +−−−−−= %;PH'( ( )( ) 5$36$3$3 +−−−−−= %;PH'( ( )( ) 5$3$36$3 +−−−−= %;P5H'( 9( 2 :::5;$;5;$;5;$;5;$; ++++ :::5;$;5;$;5;$;5;$; 5 ++++= %;P5H'( ;5;$; 5 =−−⇔ %;P5H'( ; & ?;&$ & $  5 =−+−⇔ %;P5H'( ; 5 ?;&$ 5 $  5 5 =         −       −⇔ %;P5H'( ; 5 ?;&$ 5 $  5 ?;&$ 5 $  =         +−         −−⇔ %;P5H'(       −= += ⇔ 5 ?;&$ 5 $  5 ?;&$ 5 $  %;PH'( -  U;+J+ 5 ?;&$$  + = %;P5H'( "  #5%&'(#" 0 #<)/8+=,>-  +) "( ?63365@3 6 5 =++++ %$( "+)* C +,)* ! A32$F"  +=)#J C D.M 0 "%$( %;PH'( 8 ! # $3; <≤ ,)-  G ?6$$65@$63365@3 6 56 5 =++++<++++ J+7B+=)#J C D78 ! # $3; <≤ %;PH'( 8 ! #3U$)-  G ?6$$65@$63365@3 6 56 5 =++++>++++ J+7B+=)#J C D78 ! #3U$ %;PH'( * C A%$(.E ! +=)#J C DQMA+)* ! ,32$ %;PH'( 9( 533A&3A& 55 +−−=+ 3A&533A& 55 −=+++⇔ 5 ( ) ( ) 5 5 55 3A&533A& −=+++⇔ %;PH'( ;(53(%$A&%5($3%($A5% 5555 =+−+++−⇔ %;PH'(      −= = ⇔        =+ =+ =− $3 5 $ A ;3A& ;$3 ;$A5 5 %$'( "  #6%&'( *  +$G" ! +4I" 0 +<)* 0 D$'B  += %$'(  B9" ! +&VI" 0 +<)* 0 D,)M'/8 C .4'B  += B9" ! +5?I" 0 +<)* 0 D,)M'/8 C .&'B  += %$'(  B9" ! +4I" 0 +<)* 0 D,)M'/8 C .$'B  += *  +5G" ! +$I" 0 +<)* 0 D6'B  += %$'(  B9" ! +$I" 0 +<)* 0 D,)M'/8 C .6'B  +=  B9" ! +5I" 0 +<)* 0 D,)M'/8 C .@'B  += %$'(  B9" ! +6I" 0 +<)* 0 D,)M'/8 C .V'B  += * C AI"M)"#F*  +9" ! +DB#+=/8  #'J  M,)M'/8 C .$;'B  += "  #&%&'( ".E !  W35AW53A5(WA3%5 555 ++≥++ 5555 (WA3%(WA3%6 ++≥++⇔ %;PH'( )"A .<WX9<AX"<3 −=−=−= ,".E ! 5 (.<9<"<%(.9"<6%6 −+−+−≥−−−⇔ %;PH'( 5 (.<9<"<%<6 −+−+−≥⇔ %;PH'( <6.<9<"< ≤−+−+−⇔ %;PH'( "F" C #.E ! %3YAYW( 5 U3 5 YA 5 YW 5 DE C #3PAPWU; %;PH'( J+ .<9<"<(.<9<"<% 5 −+−+−>−+−+− %;PH'(  <(.<9<"<% 5 >−+−+−⇔ %;PH'(  <.<9<"< >−+−+−⇔ %;PH'( * C A <6.<9<"<< ≤−+−+−< "  #H%&'( "(,"D=#" ! .7MB+=," C #P1F"  '/8  +=."E ,".E ! )J C ,)/ ! .:21 5 %;P5H'( R:21 5 %;P5H'( J+:2R: %;P5H'( 9(/ ! =#" ! .R1.E ! =E ! .2=E ! .2=E ! .R2V; ; 6 O B A C M D E P Q +J+R1F"  )-  +).)/  +)* C ,%;PH'( 2U ∆ R1 2 5 $  R1 %;PH'( ∆1.E ! F"  ,>M+=,MAJ ! + 2U ∆ 1 2 5 $  ∆ 1 %;PH'( /8+=,/ C ,".E !  ∆ 1R 2 5 $  ∆ 1R J+ ∆ R1 Y ∆ 1 Y ∆ 1RS 2 5 $ % R1 Y ∆ 1 Y ∆ 1R ( %;PH'( "A RS 2 5 $  ∆   1"   ∆  2 5 $ 1: ≤  5 $ :2 5  %;PH'( * ! M9L  +=3" 0 A>"K)#7"  .)- 0 K)#1,>M  += * C A RS '" C ,=#" ! ,># C F8 ! ++)* ! ,9L  += 5  5 K)#1,>M  += %;PH'( Long Hải, ngày 07 tháng 12 năm 2009 GV ra đề Trần Xuân Đài – Lê Huy & . %;PH'( )"A .<WX9<AX"<3 −=−=−= ,".E ! 5 (.< ;9& lt;"<%( .9& quot;<6%6 −+−+−≥−−−⇔ %;PH'( 5 (.< ;9& lt;"<%<6. 0 #<)" 0 # 9& quot; ! +9L  +=." ! .)+"  EO "  #&%&'()E,"D=#" ! ..E ! 9& quot;." C +)F"