CHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang1 PHN TH NHT: A THC + Kin thc b tr:-nh l Bezuot ( B-du) v h qu: S d ca php chia f(x) cho x a l f(a) f(x) chia ht cho ( x a ). -Lc Hoocner: + Bi tp: Bi 1/ Cho phng trnh : 4 3 22 2 2 3 0 x x x x + + =( 1 ). a/ Tm nghim nguyn ca phng trnh(1). b/ Tm cc nghim ca phng trnh (1). p s: a/ ( )( )4 3 2 2 22 2 2 3 0 1 2 3 0 x x x x x x x + + = + = b/ Ch c 2 nghim : 1 x = Bi 2/ Cho a thc: 5 4 3 2( ) 132005 f x x ax bx cx dx = + + + + +. Bit rngkhi x ln lt nhn cc gi tr 1. 2, 3, 4 th gi tr tng ng ca f (x) ln lt l 8, 11, 14, 17. Tnh gi tr ca f (x) vi x = 11, 12, 13, 14, 15. Gi : Chn R (x) = 3x + 5 f(11) = 27775428; f (12) = 43655081;f (13) = 65494484; f (14 ) = 94620287; f (15) = 132492410. Bi 3/ Cho a thc 3 2( ) Px x ax bx c = + + +. a/ Tm cc h s a, b, c ca a thc P (x) , bit rng khi x nhn cc gi tr tng ng l: 1,2 ; 2,5; 3,7 th P (x) c cc gi tr tng ng l : 1994,728 ; 2060,625 ; 2173,653. p s: a = 10; b = 3 ; c = 1975. b/ Tm s d r ca php chia a thc P (x) cho 2x + 5. p s: r = 2014,375. c/ Tm cc gi tr ca x khi P (x) c gi tr l : 1989. p s: x1 = 1; x2 =-1,468871126 ; x3 = =9,531128874. Bi 4/ Cho a thc 2 15( ) (1 2 3 ) Px x x = + +. a/ Tnh tng cc h s ca a thc sau khai trin theo nh thc Newton. b/ Tnh tng cc h s bc l ca x. p s: a/ 615 = 470184984566 b/ www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang2Bi 5/Cho a thc 224 2( )3x xPxx+ =+. a/ Tm gi tr ln nht, gi tr nh nht ca a thc v cc gi tr tng ng ca x. b/ Gi A(x1; max P) v B(x2; min P). Tnh di on AB. p s: a/ b/Bi 6/ Tnh | |M, k hiu | |Mc l phn nguyn ca s M ( phn nguyn ca s M l s nguyn khng vt qu M) bit rng: 2 2 22 2 24017 4015 39992010 2009 ... 20004019 4017 4001M = + + + + + + p s: | |M= 22055. Bi 7/ Tm x, bit: 2 22009 2010 0,1 20 2010 2009 0,1 x x x x + + + = + + + p s: t20,1 t x x = + + ( t > 0 ). Gii phng trnh 2009 2010 20 2010 2009 t t + = + ta c t =Tip tc gii phng trnh: x2 + x + 0,1 t 2 = 0 xBi 8/ Tnh21 1:xAx x x x x x+=+ + vi 20062007200820092010 x = p s: Rt gn A = x 1 . Th x = 4479063206 vo biu thc: A = 4479063205. Bi 9/ Tnh1 1 1 11 . 1 . 1 ... 11 2 1 2 3 1 2 3 4 1 2 3 4 ... 2010A| | | | | | | |= ||||+ + + + + + + + + + +\ . \ . \ . \ . p s: Xt dng tng qut ca hiu: ( )( )1 21 21 11 2 3 ... ( 1) ( 1)n nn nn nn + = =+ + + + + + ( )( )( )( )1.2.3...2009 4.5.6...20121.4 2.5 3.6 2009.2012. . ...2.3 3.4 4.5 2010.2011 2.3.4...2010 3.4.5...2011A = = = www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang3 Bi 10/ Tnh tng: 2002 3 2012 422 2 2 2...3 1 3 1 3 13 1A = + + + ++ + ++ p s: Ta c: 2 21 1 1 1 1 11 1 1 2 1 1mm m m m m| |= = + + |+ + \ . 21 1 1 1 1.2 1 2 1 1 m m m| | = |+ \ . nn11 1 22 2 22 2 23 1 3 1 3 1k k kk k kkp++ + += = + Vi k = 0:00 1 1 201 222 2 23 1 3 13 1p+= = +; Vi k = 1:1 21 1 2 3122 22 2 23 13 1 3 1p+= = + Vi k = 200:200 200 201200 1 201 20220102 2 22 2 23 1 3 1 3 1p+= = + . Vy 201202122 23 13 1A = Bi 11/ Tnh tng 1 2 3 99...2! 3! 4! 100!A = + + + + Ta c: ( )1 1 11( 1)! ! 1 ! 100!kAk k k= = + +

Bi 12/Cho a2 + a + 1 = 0 . Tnh tng 201120111A aa= + V ( )2 3 2 3 21 0 0 1 a a a a a a a a + + = + + = = + = ( )3 31kka a = =. Ta c: 2011 = 3.670 + 1 .Vy: ( )6702011 3.670 1 3. a a a a a+= = =.Do :3211aA a a a aa a= + = + = + = www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang4 Bi 13/ Tnh gi tr ca biu thc 4 4 4 44 4 4 41 1 1 12 . 4 . 6 ... 20104 4 4 41 1 1 11 . 3 . 5 ... 20094 4 4 4A| | | | | | | |+ + + + ||||\ . \ . \ . \ .=| | | | | | | |+ + + + ||||\ . \ . \ . \ . p s: 24 2 2 2 21 1 1 14 2 2 2n n n n n n n| | | || |+ = + = + + + || |\ . \ .\ .. Mt khc: ( ) ( ) ( ) ( )22 21 1 12 1 1 1 12 2 2n n n n n n n| | + = + + + = + + |\ .

2 2 2 2 2 22 2 2 2 2 21 1 1 1 1 12 2 . 1 1 . 4 4 . 3 3 ... 2010 2010 . 2009 20092 2 2 2 2 21 1 1 1 1 11 1 . 0 0 . 3 3 . 2 2 ... 2009 2009 . 2008 20082 2 2 2 2 2A| | | | | | | | | | | |+ + + + + + ++ + + + + ||||||\ . \ . \ . \ . \ . \ .=| | | | | | | | | | | |+ + + + ++ + + + + + + ||||||\ . \ . \ . \ . \ . \ . 22212010 20101 22. 2010 20101 20 02A| |+ + || |\ .= = + + = || |\ .+ + |\ . Bi 14/ Khai trin biu thc ( )152 2 300 1 2 301 2 3 ... x x a a x ax a x + + = + + + + Tnhchnh xc gi tr ca biu thc: 0 1 2 3 29 302 4 8 ... 536870912 1073741824 A a a a a a a = + + + p s: A = 205 891 132 094 649. Bi 15/Cho 1000 1000 2000 20006, 912; 33, 76244. x y x y + = + =Tnh 3000 3000A x y = + p s: t a = x1000 v b = y1000 ( a + b )2 =a2 + b 2 + 2ab ab = Bi 16/ Tnh217 77 77 777 ...... 777...777 293972367soA = + + + + p s: Bi 17: Cho a thc ( )4 3 255 156 Px x mx x nx = + + chia ht cho ( x 2 ) v ( x 3 ). Hy tm gi tr ca m, n v cc nghim ca a thc. p s: m = 2; n = 172; x1 = 2; x2 = 3 ; x3 ~ 2,684658438; x4 ~ -9,684658438. www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang5 Bi 18/ Tm tng cc h s ca a thc sau khi khai trin ( )( ) ( )2010 20112009 22009 2010 25 12 Px x x x x = + + + p s: Ta xt gi tr ring x = 1 P(x) = 0. Bi 20/ Tm s t nhin *n N e tho mn:( )22 2 2 2 2 2 2 21 1 1 1 1 1 1 1 2011 11 1 1 ... 11 2 2 3 3 4 20111nn+ + + + + + + + + + + + =+ p s: Cn chng minh ( ) ( )22 2 2 21 1 1 1 1 2 1a b a b aba b a b| |+ + = + + |\ . + + ( )( )2 222 2 21 1 1 1 1 1 1 1 12 .1 1 1 1 1 1a b a b a b a b a ba ba b a b a ba b| | | | | | + + + = + |||+ +\ . \ . \ . + + + = + + Suy ra: 1 1 1 1 1 1 1 11 1 ... 1 1 20111 2 2 3 1 1 2011nn n n+ + + + + + = + = + + ( )1 1 20101 2011 2010 0 2010.1 2011 2011. 1nn n nn n+ = + = =+ + Bi 21/Xc nh cc h s a, b, c sao cho a thc( )4 22 f x x ax bx c = + + +chia ht cho ( x 2 ) v khi chia cho ( x2 1 ) c d l x. p s: Dng phng php xt gi tr ring. Bi 22/ Gi s a thc( )5 21 Px x x = + + c 5 nghim x1 ; x2 ;x3 ;x4 ;x5 . t( )2100 Qx x = . Tnh tch : ( ) ( ) ( ) ( ) ( )1 2 3 4 5. . . . Qx Qx Qx Qx Qx p s: a thc( )5 21 Px x x = + + c 5 nghim x1 ; x2 ;x3 ;x4 ;x5 nn( ) ( ) ( ) ( ) ( ) ( )1 2 3 4 5. . . . . Px x x x x x x x x x x = .( ) ( ) ( ) ( ) ( )( ) ( ) ( ) ( ) ( )( ) ( ) ( ) ( ) ( )( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )1 2 3 4 52 2 2 2 21 2 3 4 52 2 2 2 21 2 3 4 51 2 3 4 5 1 2 3 4 5. . . .100 . 100 . 100 . 100 . 100100 . 100 . 100 . 100 . 10010 . 10 . 10 . 10 . 10 . 10 . 10 . 10 . 10 . 10 .A Qx Qx Qx Qx Qxx x x x xx x x x xx x x x x x x x x x== = = + + + + + www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang6( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( )1 2 3 4 5 1 2 3 4 510 . 10 . 10 . 10 . 10 . 10 . 10 . 10 . 10 . 10 x x x x x x x x x x = ( ) ( ) ( ) ( )5 25 210 . 10 10 10 1 . 10 10 1 P P (( = = + + + + = Bi 23/ Cho cc biu thc1 1 1 11 ...3 5 2009 20111 1 1 1 1...1.2011 3.2009 5.2007 2009.3 2011.1A+ + + + +=+ + + + +;1 1 1 1...2 3 4 20122011 2010 2009 1...1 2 3 2001B+ + + +=+ + + +

Tnh AB.p s: + T s ca A gp 1006 ln mu.+ Mu s ca Bgp 2012 ln t.T ca A l: 1 1 1 1 2012 2012 1 1... ... 2012. ...1 2011 1005 1007 1.2011 1005.1007 1.2011 1005.1007| | | | | |+ + + + = + + = + + |||\ . \ . \ . Mu ca B l: 2012 1 2012 2 2012 2011 2012 2012 2012 1 2 2011... ... ...1 2 2011 1 2 2011 1 2 20111 1 1 1 1 12012 2012. ... 2011 1 2012. ...2 3 2011 2 3 20111 1 1 1 12012. ... 1006:2 3 2011 2012 20AB | | | |+ + + = + + + + + + ||\ . \ .| | | |= + + + + = + + + + ||\ . \ .| |= + + + + = |\ .1006.201212 = = Bi 24/ H s ca x2 v x3 trong khai trin nh thc( )2053 x + tng ng l a v b. Hy tnh t s ab ? p s: ( ) ( ) ( ) ( ) ( ) ( )20 20 19 18 17 00 0 1 1 2 2 3 3 20 20 5 5 5 5 5 520 20 20 20 203 3 3 3 3 ... 3 x C x C x C x C x C x + = + + + + + ( ) ( )518 172 3 5 520 2033 ; 3 0, 20766aa C b Cb= = = ~ Bi 25/Khai trin biu thc( )( )2821 7 . 1 1 10 .... x ax x bx + + = + + + Hy xc nh a v b ? p s: ( )( )( ) ( )282 1 2 2 2 28 81 7 . 1 1 2 7 7 . 1 1. 1 . ... x ax x x C ax C ax + + = + + + + + Ta c:181 2 28 810 2 7 0, 588641, 6144.2 7 7C a abb C a Ca= + ~ ~= + + www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang7 PHN TH 2:HM S V TH Bi 1: Cho hai ng thng 1 3(1)2 2y x = + v 2 7(2)5 2y x = + ct nhau ti im A.Mt ng thng (d) i qua im (5; 0) H v song song vi trc tung Oy ln lt ct (1) v (2) theo th t ti B v C. a/ V trn cng mt h trc to th ca cc hm s trn. b/ Tm to cc im A, B, C bng phn s. c/ Tnh din tch tam gic ABC ( vit di dng phn s ) d/ Tnh s o mi gc ca tam gic ABC ( chnh xc n pht ). p s: ( )

0 0 020 47 3 125; ; 5; 4 ; 5; ;9 18 2 3648 22'; 63 26'; 68 12'.ABCA B C SA B C| | | |= ||\ . \ .= = = Bi 2: Tnh gn ng to giao im ca ng thng 2 5 6 0 x y + = viElp 2 2116 9x y+ = p s: 1 12 22, 63791842; 2, 2551673683, 966638175; 0, 386655275x yx y~ ~~ ~ Bi 3 : Cho hai ng trn c phng trnh tng ng l ( ) ( )2 2 2 21 210 6 1 0 ; 6 8 12 0 x y x y C x y x y C + + + = + + = a/ Vit phng trnh ng thng i qua tm ca hai ng trn b/ Tnh to giao im ca ng thng ni trn vi ng trn (C1) p s:1 12 2/ 2 11 0./ 10,13809; 0, 4309534840,13809; 5, 569046516a x yb x yx y =~ ~~ ~ www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang8Bi 4: Tnh gi tr gn ng to cc giao im ca Hyperbol 2 219 4x y = v ng thng 8 4 0 x y + = p s:1 12 23, 29728; 0, 912160523, 00579; 0,124276727x yx y~ ~~ ~ Bi 5: Cho tam gic ABC c cc nh ( ) ( ) ( )1; 3 ; 5; 2 ; 5; 5 A B C a/ Tnh gn ng di 3 cnh v din tch tam gic ABC b/ Tnh gn ng ( , pht, giy ) s o ca gc A. p s:

0/ 8, 08276; 10, 44031; 4, 47214/ 162 53' 50''a AB BC ACb A~ ~ ~~ Bi 6: Tnh gn ng to giao im ca cc th hm s3 212 ; 2 14 3 2x xy x y x = = + p s: Bi 7: Trong mt phng to Oxy, cho cc im ( ) ( ) ( )2; 3 ; 4; 6 ; 1; 1 A B C Xc nh tm I v bn knh R ca ng trn ngoi tip tam gic ABC. p s: 177 17; ; 6, 0385826 26I R| |~ |\ . www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang9 PHN TH 3:PHNG TRNH V H PHNG TRNH Bi 1:Gii h phng trnh 22 22 14 4 7x xyx xy y =+ = p s: T phng trnh (1) ta c x khc 0 22 1 xyx= th vo (2) 22 22 4 22 1 2 14 4 . 7 8 7 1 0x xx x x xx x| | + = = |\ . H phng trnh c hai nghim l: 1 1;1 1x xy y= = = = Bi 2: Tnh x ca phng trnh sau theo a, b dng 1 1 1 a b x a b x + = + p s: 224 4 14b axb += Bi 3: Gii phng trnh178408256 26614 1332007 178381643 26612 1332007 1 x x x x + + + + + =p s: 1 2175744242; 175717629175717629 175744242x xx= =< < Bi 4: Gii h phng trnh sau( )( )3 22 213 26102 2009 4030056 0(1)4017 1 4017 3(2)x x xx x y x =+ + + + = p s: Gii phng trnh (1) c x = 2008 th vo phng trnh (2) tnh y. 20082006, 268148xy== Bi 5: Gii phng trnh2 3 3 5 5 2 x x x x x x x = + + p s: t bin s ph: 2 ; 3 ; 5 x a x b x c = = = vi a, b, c > 0 www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang10Suy ra: 2 2 23060( )( ) 22 3 5 11 30( )( ) 360( )( ) 519 3060aa b a cx a b cb a b c bx ab bc cac a c bc=+ + = = = = + + = = = + + + + == Bi 6: Tm nghim nguyn dng ca h phng trnh sau100(1)5 3 100(2)3a b cca b+ + =+ + = p s: abc= = =; abc= = =; abc= = = Bi 7: Cho tam gic ABC c 03 2 180 C B + = . a/ Vit biu thc tnh AB theo BC v AC. b/ Bit 3 cnh ca tam gic l ba s t nhin lin tip. Tnh din tch tam gic ABC ? p s: a/ Ta c: 03 2 180 2 C B A C B A + = = + ln nht. Trn BC ly im D sao cho ; BAD C ABD CBA = A A ng dng. 2 2. ( ) AB BC BD AB BCBC CD = = . M CD = AC ( ) AB BCBC AC = b/ Ta c: BC > AB; BC > AC. Gi n 1 ; n ; n + 1 l di 3 cnh ca tam gic. Suy ra: BC = n + 1. + Nu AB = n; AC = n 1: | |2( 1). ( 1) ( 1) 2( 1) 2( 1) n n n n n n n n = + + = + = + ( v nghim ) + Nu AB = n 1 ; AC = n: | |201 ( 1). ( 1) 1 ( 1) 2 1 13nn n n n n n n n nn=

= + + = + + = + = Do 3 cnh ca tam gic l 2; 3; 4.Dng cng thc Herong tnh S . www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang11Bi 8: C 100 ngi trong c n ng, n b v hc sinh p on di 60 mt. Nhm n ng p mi ngi 5 mt, nhm n b p mi ngi 3 mt, nhm hc sinh p mi ngi 0,2 mt. Tnh s n ng, n b v s hc sinh ? p s:6100(1)45 3 60(2)905aa b cbca bc=+ + = = + + = =

Bi 9: Gii h phng trnh 2 2 2 2(2 ) 5(4 ) 6(2 ) 0(1)12 3(2)2x y x y x yx yx y + + =+ + = p s: Chia 2 v ca phng trnh (1) cho 2(2 ) 0 x y =. Ta c: 2 2 22 21 1(2 ) . 5(4 ). 6 0(1)(2 ) (2 )12 3(2)2x y x yx y x yx yx y+ + = + + = t : 23812( ) 5 6 0 1 4(2 ); 32 3 33412xuvyuv uvu x y v uvx y u vxu vy

=

= =

+ =

= + = =

+ = =+ =

=

Bi 10: Tnh nghim gn ng ca h phng trnh2 22 22 3 74 3x yx y xy + = + = p s: 111, 86911;0, 06544xy~~ 211, 86911;0, 06544xy~ ~330, 77820;1, 38910xy~~440, 77820;1, 38910xy~ ~ www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang12Bi 11:Tm cp s ( x; y ) nguyn dng tho mn phng trnh 5 23 19(72 ) 240677 x x y = p s: ( )55 253 2406773 19(72 ) 240677 72193 24067772 ( : 9) 32; 5 ; ( 32; 4603)19xx x y x yxy x dk x x y x y = = = > = = = = Bi 12: Gii phng trnh v h phng trnh sau: a/ ( )( ) ( )( )6 811 2 1 4 x x x x+ =+ + + b/ 1 113 6 7x y z x y zx y z + + + + + +== = Bi 13: Gii h phng trnh sau: a/ 1 1 1333( )1 1 1 24 ( )245 ( )11 1 15x y zyx y x z x y zxx y y z x y zzy z xx z y z x y zyz x y+ =++ = + + = + = + = + + + =+ = + + + =+ t x = 2k, y = 3k, z = 6k .Suy ra: k = 11/6 nn ( x, y, z ) = ( 11/3; 11/2; 11 ) Bi 14: Gii cc phng trnh nghim nguyn sau: ( )2 3 2 32 2 2/ 6 3 10 2/ 7 1 3 2/ 2 2 10 25 567a xy x yb x y xyc x xy y yz z+ = + =+ + + = Bi 15: Gii cc h phng trnh sau: a/ 6 5( )3 2( )7 10( )xy x yyz y zzx z x= += += + b/ 65431 27x yx yy zy zz xz x=+=+=+ Bi 16: Gii cc phng trnh: a/2 3 10 2 5 x x + + = ;b/ 31 2 5 x x = www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang13 PHN 4:LI SUT V TNG TRNG Cng thc: + Dn s:( )1nA a r = + trong A l s dn sau n nm; a s dn gc; r l t l tng dn s trung bnh hng nm; n l s nm + Li kp dng I:( )1nA a r = + trong A l s tin nhn c sau nthng;a s tin gc; r l li sut ca ngn hng hng thng ; n l s thng + Li kp dng II:( ) ( )1 1 1na r rAr (+ + = trong A l s tin nhn c sau nthng; a s tin ng ca mi thng ( nh nhau ) ; r l li sut ca ngn hng hng thng ; n l s thng Bi 1: a/ Mt s tin 10 000 000 ng c gi vo ngn hng theo li kp vi li sut0,7%/ thng. Hi sau 2 nm th rt v c vn ln li l bao nhiu ? p s: 11 822 444,76ng b/ Mun c 100 000 000 ng sau 1 nm th phi gi ngn hng mi thng mt s tin bng nhau l bao nhiu nu li sut l 0,6%/ thng ? p s: 8 013 814,456ng Bi 2: Dn s ca mt nc l 80 triu ngi, mc tng dn s l 1,1%/ nm. Tnh dn s ca nc sau 20 nm ? p s: Bi 3: (Thi khu vc 2007 ) Mt ngi gi tit kim 100 000 000 ng vo mt ngn hng theo mc k hn 6 thng vi li sut 0,65%/ thng. a/ Hi sau 10 nm ngi nhn c bao nhiu tin ( c vn ln li ) ngn hng. Bit rng ngi khng rt li tt c cc nh k trc . p s: 214 936 885,3ng b/ Nu vi s tin trn, ngi gi tit kim theo mc k hn 3 thng vi li sut 0,63%/ thng th sau 10 nm nhn c bao nhiu tin ? p s: 211 476 682,9ng Bi 4: Mun c 1 t ng sau 31 thng th phi gi ngn hng mi thng mt s tin bng nhau l bao nhiu nu ngn hng chp nhn li sut l 0,6%/ thng. So vi s tin thc gi th ngn hng phi tr li bao nhiu sau 31 thng ? p s: + Hng thng phi gi ngn hng l: 29 271 780,55 ng www.VNMATH.comCHUYN BI DNG HC SINH GII CASIO 9I S HC GV bin son: CAO KHC DNG - Trng THCS Nguyn Ch Thanh - Huyn ng Ho.Trang14+ S tin li nhn c t ngn hng l: 92 574 802,95 ng Bi 5:Mt chic xe my tr gi 11 000 000 ng c bn tr gp 12 thng, mi thng tr gp 1 000 000 ng v bt u tr sau khi nhn xe 1 thng. Tnh li sut tin trong 1 thng ? p s: 1.36%/ thng Bi 6:Mt ngi mua 1 my tnh xch tay ( Laptop) tr gi 10 000 000 ng vi tho thun tr gp mi thng 1 000 000 ng. Bit rng ngi y phi tr 11 thng mi xong. Hi cuc giao dch ny da trn li sut bao nhiu %/ thng ? Gii: Sau ln tr th 1: s tin cn li l( )1 % a r b + Sau ln tr th 2: s tin cn li l ( ) ( ) ( ) ( )21 % 1 % 1 % 2 % a r b r b a r b r( + + = + + Sau ln tr th 3: s tin cn li l ( ) ( ) ( ) ( ) ( )( )2 31 % 2 % 1 % 1 % 2 % 1 % a r b r r b a r b r r (+ + + = + + +

Sau ln tr th n: s tin cn li l :( ) ( )1 % %na r bn r + + Ta c phng trnh: ( ) ( )1110000000 1 % 1000000 11 % 0 0, 8775 87, 75% r r r + + = ~ = Bi 7: Dn s ca mt thnh ph nm 2007 l 330 000 ngi. a/ Hi nm hc 2007 2008 , d bo c bao nhiu hc sinh lp 1 n trng bit trong 10 nm tr li y t l tng dn s mi nm l 1,5% v thnh ph thc hin tt ch trng 100% tr em ng tui vo lp 1 ?b/ Nu n nm hc 2015 2016 thnh ph ch p ng c 120 phng hc cho hc sinh lp 1, mi phng hc c 35 hc sinh th phi kim ch t l tng dn s mi nm l bao nhiu ? ( Bt u t nm 2007 ). Gii: a/S dn nm 2007 : D2007 = D2006 + D2006. 0,015 = D2006.(1 + 0,015)2006330000(1 0, 015)D =+ 2000 7330000(1 0, 015)D =+; S tr em tng nm 2001 n nm 2007 ( trn 6 tui vo lp 1 ) l: 7330000.0, 015 44600(1 0, 015)~+( ngi ) b/ Gi x% l t l tng dn s cn khng ch ( )20082009330000 330000. % 330000(1 %)330000(1 %). % ... 35.120 1, 25%D x xD x x x = + = + = + = = = www.VNMATH.com