CAC DANG HOAT DONG THANH PHAN CHU YEU CUA HOAT DONG BIEN DO! DOI TUONG TRONG DAY HOC TOAN • * • • • 6 TRUNG HOC PHO THONG O GS, TS, OAO TAM* TRL/ONG BUI THUY DUONG*" 1 Nhu chiing ta dd bilt Hogt dgng[.]
CAC DANG HOAT DONG THANH PHAN CHU YEU CUA HOAT DONG BIEN DO! DOI TUONG TRONG DAY HOC TOAN • * • • • TRUNG HOC PHO THONG O GS, TS, OAO TAM* - TRL/ONG BUI THUY DUONG*" Nhu chiing ta dd bilt: Hogt dgng (HD) bien ddi ddi tugng (BDDT) Id qud trinh chu thd dung cdc thao tdc tu dua tren tri thuc, kinh nghiem da cd deed the xam nhgp vdo ddi tugng nghien cuu nhdm bien ddi cdu true cua ddi tugng, bao gdm cdc mdi lien hd, quan he, ke cd hinh thue cua ddi tugng de bien ddi thdnh sdn phdm Nhu vdy, bdn chdt cua HD ndy Id bien ddi vd xu If thdng Hn mdt HD quan trqng giup hqe sinh (HS) gidi quylt vdn de (GQVD) mdt cdch sdng tqo Thye tien dqy hqe eho thdy, HS thudng gdp khd khdn, lung hjng vi cdc em khdng bilt phdi huy ddng kiln thue nhu t h l ndo xdm nhdp, biln ddi cdc ddi tuqng todn hqc Trong ehuong trinh mdn Todn d trung hqc phd thdng, moi ndi dung dqy hqc d i u lien he mdt thilt vdi cdc HD hqc tdp eua HS; ung vdi mdi ndi dung, khdng ehi ed mdt HD md cd t h l ed nhilu HD lien quan Cdc HD ndy khdng tdn tqi ddc ldp md bd trq hodc bao hdm Idn nhau; mdt HD ed t h l xudt hien nhu Id thdnh phdn cuo mdt HD khde Viee phdn tdeh mdt HD thdnh cdc hoqt ddng thdnh phdn (HOTP) nhdm tdp eho HS bilt tdeh rieng nhi?ng HDTP khd hodc quan trqng edn thilt Dudi ddy, chung tdi trinh bdy mdt sd HDTP ehu yeu cuo HD BDDT Cdc HOTP chu yeu a) HD du dodn: Dy dodn Id phuong phdp duqc ung dyng rdng rdi nghien cuu khoa hqe, dd Id sy edn cu vdo cdc nguyen If, gid thuyit dd cho de neu len nhCrng hien tuqng vd quy ludt chua bilt Id bude nhdy vqt tu gid thuyit song kit ludn Dudodn cd vai frd thue ddy qud trinh GQVD todn hqe Phuong phdp ndy khdng ehi giup ngudi hqc phdt hien md cdn Hm duqc nhCrng Idi gidi hay, trdnh duqc su md mdm khdng edn thilt Vidy 1: Cho dilm M di ddng tren dudng trdn # tdm O dudng kinh AB Ggi M' Id mdt dilm tr§n doqn MH eho /M/' = ^///W, frong 66HeAB vd Xf/l /IB Tim quy tfch d i l m M' M di ,^_^-„ chuyin tren (O) Bdi todn quy tfch ndy ''"*''^"' Id mdt vf dy diln hinh eho HD du dodn O ddy, HS cd t h l du dodn theo cdc cdch sou: 1) Vdi St/ ho trq cuo md hinh ddng, HS thong qua quan sdt vet cuo M' Hinh M di chuyin d l du dodn quy tfch cuo M' 2) Ddc biet hdo dieu kien cua bdi todn de duo du dodn: Gid su dilm O cd tqo O(0,-0) Gqi Mi^x^.y,^ thdo mdn ) , dd, tqa cua dilm M phuong trinh dudng trdn: r + ^ - = /?-(*) Gqi tqo cuo diem M' la M\x^^.\y^ ) , HM'=-HM nen to duqc Thay tqo cue M' vdo (*) ta duqc: 2 [3) Tu ddy, to suy fr>a eua dilm M' thda man •=i phuong trinh: if)' * Tmdng Bai hoc Vinh "Cao hQC K18 Tnrding Sal hpc sir pham - Dai hpc Hue Tap ehi Giao due so (ki 1.10/2011) Ddy chfnh Id phuong trinh cua elip Mqc do, khdng cd mqt phuong phdp ddm bdo tuyet dd'i viec hqc thdng thqo cdch du dodn, chung ta cung cd mqt sd dudng thdng dyng d l d u dodn nhu: d u dodn bdng thao tde dqc biet hda, tuong tu hda, tdng qudt hda, quy nqp hodc thdng qua quan sdt, thue nghiem, phdn loqi so sdnh b) HD lien tudng va huy dgng kien thuc: Sy phdt t r i l n nhqn thue Id qud trinh tfch luy cdc mdi lien tudng Trong qud trinh Hm tdi cdch thue d l djnh hudng gidi bdi todn, nhieu chung to phdi Hin hdnh b i l n ddi bdi todn thdng quo ede HD lien hrong N h d HD ndy, ta ed t h l chuyin ddi hrqng cdn nghien cuu sang dd'i hrqng mdi, quen thudc hon d l de nghien cuu Di kem vdi HD lien hrdng Id khd ndng huy dqng k i l n thuc vd kT ndng chuyin hdo ede lien tudng Vidy 2: Cho hinh hop ABCD.A^B,Cp^ Dyng dudng thdng MN eho M G AC^,N chilu song song phuang DA, len mp(A 6,C,D,j d l Hm d i l m N Chu y rdng Nchfnh Id dnn cua M qua phep chieu song song Ndng luc lien tudng vd huy dqng kiln thuc ed vai trd quan trqng t i l n trinh nhqn thuc vd phdt trien trf tue eua HS N l u ngudi hqe khdng cd ndng luc ndy thi ndng luc GQVD se bj hqn e h l , cdch nhin ve todn hqe se eye bq, rdi rqc Tuy nhien, dung frude mqt vdn de ey t h l , khdng phdi luc ndo mqi su lien tudng vd huy dqng deu cd fch eho viec gidi q u y l t vdn de Cdn chgn Ige thdng qua cdc phep thu sai de t i l n tdi mqt sy lien tudng vd huy dqng phu hqp nhdt Vidy 3: Chung minh n l u a, b, c Id ddi cdc cqnh cua mdt tam gidc thi o^ + £>^ + c^ < 2(ab + bc + ca) Gid thuyet cua bdi todn ndi d i n cdc cqnh cua mdt tam gidc, vi vdy, HS ed t h l huy dqng cdc djnh If, tfnh chdt dd b i l t ve quan he gii?a cdc cqnh cua mqt tam gidc, chdng hqn nhu: a > be; a < b+c; cP = hi' + dieu kien cho frude Tuy nhien, frong todn hqc, ed nhCrng vdn d l md d i l m xudt phdt khdng ehf cd root, nhung chi ed mqt d i l m k i t thue ( d i l u cdn chung minh) Khi d d , HO lam ngugc (suy nguoc) xudt phat tu dieu cdn chung minh Id rdt cdn thilt Vf dy 8: Tdng eua hoi so Id 12, tieh eua hai so Bdi todn ndy khdng phdi Id Heu b i l u frong ehuong trinh todn phd thdng, nhung Id mqt minh hqo khd dn hrqng eho sue mqnh cuo HD suy lugn nguqe (ldm nguoc) De gidi q u y l t bdi todn ndy, HS thudng di jc+>' = 12 sen gidihe: xy = Tap Chi Giao due so (ki i -10/2011) vd tim d u q c ( x , > ; ) = ( + 4x/2,6-4N/2) 12 X y + 4V2 6-4>y2 36-32 Khi 60: Ve nguyen tic (Tiep theo trang 35) = Id chue ndng cud'i cirng cua ngdn ngi?, cung Tuy nhien, edn ehu y rdng thuc hien qud trinh nhu dqy GT khdng phdi Id myc dfch cudi ndy, HS eung de mdc cdc sai ldm dqi so Nhung vdi cung cua viec dqy Heng GS Do Huu Chdu phuong dn ldm nguqe, HS se Hm duqc k i t qud nhanh eho rdng: «Mqt ngdn ngi? hqc hudng tdi chdng vd trdnh duqc nhCrng sai ldm cd t h l mdc phdi hoqt dqng hdnh chuc cua ngdn ngi? khdng Xudt p h d t t u td'ng e d n t i m , ta thd'y n g a y : the xem nhe hoqt dqng hdnh chuc phyc vy tu N l u nhdn mqnh vdo chuc ndng GT thi d d Id vi hoqt dqng GT de quan sdt hon, X y xy k i t qud nghien cuu Ilnh vyc ndy dd Phdt hien duqc nhCrng HD hqe tdp tuong thich khd phong phu chu khdng phdi vi chue vdi mdt ndi dung d q y hqe nghia Id ngudi hqe dd Hm ndng ldm cdng cy tu Id khdng ddng ro duqc mdt d u d n g d l c h i i m ttnh nqi dung d d ke" (7) Mqc du khdng «tuyet ddi hda mqt va eung Id cdch d l G V k i l m tra xem HS cd dqt duqc chuc ndng" nhung cd t h l thdy, nguyen tde cae mye Heu g i d o dye hay khdng, dqt duqc d i n muc GT vdn ludn Id mqt nguyen tdc quan trqng ndo Trong q u d trinh t d chuc d q y vd hqc todn, DH Hlng, ddc biet Id DH Heng Viet d viec quan tdm d i n cdc HDTP cua HD BDDT se giup H I U hoc G fch cho HS viee iTnh hdi tri thuc, khdm phd vd GQVD mdt cdch ehu d d n g vd sdng tqo Neu G V cd t h l Idng ghep cdc HD ndy vdo nqi dung d q y hqc (1) V.B Kasevich Nhung yeu 10 00"saciia ngdn mqt cdch linh hoqt se g d p phdn ndng cao hieu qud ngir hoc dai cmmg NXB Gido due, H 1998 hqc tdp cho HS • (2) Tid'ng Viet vd phuong phdp dgy tiing (Ki 1-£1Z-11- Tai lieu tham khao Nguyen Bi Kim Phinmg phap day hoc mon Toan NXB Dgi hge supham, H 2008 Dao Tam Td chuc day hoc mdn Toan d truong trung hpc phd thdng, NXB Dgi hge suphgm, H 2010 Dio Vin Trung Lam the nao de hoc tdt toan phd thdng NXB Dgi hge qude gia Hd Ndi, H 2001 Posamentier & Stephen Krulik Problem solving strategies for efficent and elegant solutions Corwin Press, inc 1998 Ronald & Hector Knowledge represention and reasoning Elsevier, Inc 2004 SUMMARY This article want to make clearly the object changing activity that is mentioned in learning and teaching Mathematics Following close on this target, we turn to determine the component activity forms of this activity Through clear making the component activities, we'd like to emphasize the importance of exercising object changing activity for student in learning and teaching Maths Thence, to help them achieve the necessary skills to flexibly and creatively be mobilizing knowledges, discovering and tAaths problems solving Tap chi Giao due so (ki i 10/2011) ye'u hoi thao khoa hoc 2001 Dai hpc qud'c gia Ha NOi, DH quO'c gia TP H6 Chi Minh) NXB Dgi hge qudc gia Hd Ngi (3) H.H Stem Fundamental Conceptsof Language Teacliing Oxford University Press, 1997 (4) Le Phuong Nga Phuong phap day hoc Tieng Viet it tieu hoc n NXB Dgi hge suphgm, H.2009 (5) Nguyen Tri Mdt sd' van de day hoc tieng Viet theo quan diem giao tiep d tieu hoc NXB Gido due Viit Nam, H 2009 (6) BO GD-DT Dy an Phat trie'n giao vien tie'u hoc Tdi liiu bdi duomg Doi m&i phuong phdp dgy hge & tiiu hge (bing hinh) (7) DO HQ'U Chiu Giao trinh gian yeu v^ ngudung hoc NXB Gido due, H 1995 SUMMARY Teaching-oriented communication is not only a basic direction of renovating Vietnamese teaching method but also one of specific principles of teaching Vietnamese Principle of communication dominates most strongly Vietnamese teaching program at primary level: objectives, contents, teaching method and evaluation of students' learning results # ... NXB Dgi hge supham, H 2008 Dao Tam Td chuc day hoc mdn Toan d truong trung hpc phd thdng, NXB Dgi hge suphgm, H 2010 Dio Vin Trung Lam the nao de hoc tdt toan phd thdng NXB Dgi hge qude gia Hd... phdi "bd''t ddng thuc" nhu dieu cdn chung minh c) HD chuyen ddi hinh Hiuc - ngi dung cua ddi tugng: Trong dqy hqe todn hqc, nqi dung thdng dd N h u vdy, de dung duqc MN, HS se cua mdt ddi tuqng Id... HS edn thilt phdi su dyng suy lugn quy ngp vdi diem hA(x;y) vd x G V''6 (o;il Giai dogn quy ngp: Trong giai doqn ndy, HS se Hen hdnh Hm gid thuyit quy nqp Ddu Hen, HS HD chuyen ddi ben mot ngi