Đề HSG L9 (7-12) - HD giải ( 3Y)

Đề HSG L9 (7-12) - HD giải (.3Y)

4
305
0

De HSG l9 ductho 2013 2014 toan

... =+Bài 5: a) ( ) ( )3 3 2 2x y 3 x y 4 x y 4 0+ + + + + + = ( ) ( ) ( ) ( ) ( )2 2 2 2 2 2x y x xy y 2 x xy y x 2xy y 4 x y 4 0⇔ + − + + − + + + + + + + = ( ) ( ) ( ) ( ) ( )22 2 2 21x ... ABGC AC= (2 ). Từ (1 ) và (2 ) ta có: ( )GB AHGB.HC AH.GC GB.HC AH. BC GB GB.HC AH.BC AH.GBGC HC= ⇒ = ⇒ = − ⇒ = −AH.GB GB.HC HD. BC⇒ + = (Vì HD = AH) ( )GB. AH HC HD. BC⇒ + = GB HD BC AH ... + = = −  Từ đó ta tìm được (x; y) ∈ { (- 3 ; 3); (- 4 ; 4)}Cách 2: ( )+ − − = ⇔ + − − = ⇔ − + − = −2 2 2y 2xy 7x 12 0 4y 8xy 28x 48 0 4y 49 4x 2y 7 1 ( ) ( )2y 7 2y 7 4x 1⇔ − + + = − ta...

4
341
0

HD giai de HSG tan yen I - dao nhien huong

...

1
286
0

Chuyen de HSG CM dang thuc co HD giai

... đợc:cabcabccbcabacbbcaabbcaaabccacbbbcaaP+++++=+++++=222222222222222 )() ( )() ( )() ( 222cbacbccbacbabbcabcaaa++++=) )(( ) )(( ) )(( ) )(( ) )(( ) )(( 222222cacbccbbabbacaacacbcbcbabbacaa+=++=) )() (( )( ) )() (( )( ) )() (( )( 222bacacbbaccacbbacabcbbacacba+==++=+=) )() (( )( ) )() (( )() ( )( 22222222cbbacabcaccbabcbacbbacabacacbcba[ ]1) )() (( ) )() (( ) )() (( )() ( )( ) )() (( ) )(( ) )() (( )() )(( )( ) )() (( )( 2222222===+=++=++=cbbacacabacbcbbacacbcbaacbcbbacabcacabacbcbbacacbbccbcbacbacbbacabccbacabcbaBài ... đợc:cabcabccbcabacbbcaabbcaaabccacbbbcaaP+++++=+++++=222222222222222 )() ( )() ( )() ( 222cbacbccbacbabbcabcaaa++++=) )(( ) )(( ) )(( ) )(( ) )(( ) )(( 222222cacbccbbabbacaacacbcbcbabbacaa+=++=) )() (( )( ) )() (( )( ) )() (( )( 222bacacbbaccacbbacabcbbacacba+==++=+=) )() (( )( ) )() (( )() ( )( 22222222cbbacabcaccbabcbacbbacabacacbcba[ ... a).=++++++=+++++=+++=222222222222222) 1( 12) 1( ) 1( ) 1() 1( ) 1( 111aaaaaaaaaaaaaaaA[ ]2222222222222222) 1( 1) 1( ) 1( 1) 1(2 ) 1( ) 1( 1) 1(2 ) 1( ) 1( 122) 1( +++=+++++=+++++=+++++=aaaaaaaaaaaaaaaaaaaaaa22) 1( 1+++=aaaa;...

6
461
4

74 DE+HD GIAI HSG TOAN 8

... 2 )(2 x2 + 3x + 1) = (x 3)(x 2)(x + 1 )(2 x + 1).b). P(x) = (x 3)(x 2)(x + 1 )(2 x + 1) = (x 3)(x 2)(x + 1 )(2 x 2 + 3) = 2(x 3)(x 2)(x + 1)(x 1) + 3(x 3)(x 2)(x + 1) P(x) 6 M ( fcm).Câu 2: ... HảiBD HSG Toán 81Câu 1: (2 điểm) Phân tích thành nhân tửa) a(x2 + 1) x(a2 + 1)b) x 1 + xn + 3 xn HD: a). a(x2 + 1) x(a2 + 1) = ax2 a2x + a x = ax(x a) (x a) = (x a)(ax ... HSG Toán 8 HD: a). P(x) = 2x4 7x3 2x2 + 13x + 6 = 2x4 6x3 x3 + 3x2 5x2 + 15x 2x + 6= (x 3 )(2 x3 x2 5x 2) = (x 3 )(2 x3 4x2 + 3x2 6x +x 2)=(x 3)(x 2 )(2 x2...