RlN UlYiN 1NA0 lAC TO ROY POANIICH VA IRNG OOP GHO HOC SINH I t P 9 IHRNG OUA GAC RAI TOAN GIAI RANG P H I N G PHAP Vt IHtM HINH PHO ThS BACH PHUONG VINH* Mdt bai toan (BT) hinh hpc ed the cd nhieu ea[.]
RlN UlYiN 1NA0 lAC TO ROY POANIICH VA IRNG OOP GHO HOC SINH ItP IHRNG OUA GAC RAI TOAN GIAI RANG PHING PHAP Vt IHtM HINH PHO ThS BACH PHUONG VINH* M dt bai toan (BT) hinh hpc ed the cd nhieu each giai khae nhau, nliung cd nhQng BT vdi dQ kien da cho hpc sinh (HS) cd t h i gap bitdc, khdng tim each giai nlu khdng ve ttidm hinh phij Odi vdi nhung BT dd.vlgc ve them hinh phy giup HS tim dupe lijl giai d l ddng va thudn Ipi hon, thdm chi cd BT phai ve them hinh phy mdi tim dupe Idi giai Vd'n d l ddt Id lieu ed phuong phap (PP) ve them hinh phy ehung cho eac BT hinh hpc hay khdng, ve them hinh phu nhu f h l nao de thudn Ipi cho vide giai toan vd phat trien tu eho HS? Oe tao dupe mdt hinh phu lien kit tudng minh cdc mdi quan he toan hpc giua dilu kign da cho (gia ttiilt) vdi dilu kien phai tim (kit luan), ddi hdi HS phai thyc hidn cde thao tac tu duy: phdn tich (PT), td'ng hpp (TH), so sdnh, tuong ty hoa, ddc bigt hod, khai quat hod ; dd, ttiao tdc tu ptidn tich va td'ng hpp (PTVTH) giu vai trd nin tang Giao vien (GV) ein trang bj eho HS nhung kiln thQc, kT ndng can thilt va eac bien phap PT de tim each ve hinh phu phu hpp cho mdi BT; tQ dd, HS cd t h i chu ddng tim dupc tiudng giai quydt vd'n d l vd ren luyen eac thao tactarduy PTVTH kit ludn (ylu td phai tim), tim mdi lien he glQa chiing o l giai quy^ BT, ta cd f h l tach, chia BTttianhtaing tmdng hpp lidng le, vlec giai quylttaingvan de nhd se d l ddng hon TH ode ylu td, mdi quan he glQa eac yd'u td vQa PT ehung ta se nJt dupc kit ludn mdi; TH each giai ciia cde BT bd phdn, lien kit ldi giai eua BT ban dlu PTVTH la hal thao tae tu trai ngupc nhau, chung la hai mat dd'i lap cua mdt qua trinh ttidng nhat Tuy nhien, qua trinh giai toan, HS cd f h l ttiyc hign lien tilp eac thao tac PTVTH d l tim ldi giai, khaittiac,phdt triln BT Qua dd, HS ed ttie ndng eao ndng lyc giai toan cho HS PP ve them hinh phu va mot sd'loai hinh phu thudng dupc sir dung b'ong giai toan hinh hpc 1} Yiu ci'u cua vlec vi them hinh phy Vige ve them hinh phu nhdm mue dich tim each giai BT, lam cho BT bd nen don gian han, giup HS dua dupc nhQng ldi giai hay, ddc dao Mudn vdy, nd phai Id kit qua cua eae hoat ddng tri tug: PT, TH, tuong ty d l gan kit mdi quan he giQa kiln thQc da cd vdi gia thilt da cho vd kit ludn phai tim d l giai quyet BT Vethem hinh phy ludn phai tudn theo cac phep dyng hinh CO ban va can chu y Id khdng dyng hinh phu mdt cdeh tidn ma phai lya ehpn each dyng thich Phan tich va tdng hop 'PTIi dung tride chia cai toin there tung hpp, thda man cac tinh chat nao dd cua BT phan, hoac tach tdng thude tinh hay khia canh 2} Mgt so' loai hinh phu thudng duac sir rieng biet nim eai toan the do"; "TH la dung dung giai toin hinh hgc: • d m f m n g dilm tri dc htfp lai cie phan cua eii toan the, hoac ket cua dognttidng;dilm eh'ia hay chia ngoai doan hgp lai nhung thude tinh hay khia canh khic ttidng dd cho theo mdt ti sd thieh hpp;jiao diem eua nim tmng eii loan thedd"{\) Theo Tu dien Tieng cac hinh, ; - Doan thang, dudng thing, fra.'ndi hai Viet: VTIaphin chia that su hay bing tudng tugng did'm cho bude; keo dai mpt doan thing cho tmde; mgt dd'i tugng nhan Me cic ye'u to, trai tai mdt diem cho tmde, dyng dudng thdng song song vdi TH; THIi to hgp bing tudng tugng hay thatsu,^ (hode vudng gdc) vdi mpt duiimgttiangda cho; dung cic yiu td'rieng re nio dd lim mdt ehinh the, dudng phdn giac cua mdt gdc cho budc; dyng dudng trai vdiPr(2) Theo Nguyen Ba Kim: "PTla tieh ttidng di qua mdt diem cho tmde hepttianhvdi ducrig (trong tu tudng) mdt hg thd'ng thinh nhung vat, tieh thing khae mdt gdc bdng gdc eho tmde; tQ mpt did'm mot vat thinh nhung bd phin rieng le; TH la lien ket chottudcdyng tiep bjyin vdi dudng bdn da cho; dyng (trong tu tudng) nhung bd phin mdt vat, lien ddy cung chung eua hai dudng trdn giao nhau; vd ket nhieu vit thinh mdt he thong"{3) tia ddi Clia mpt tia; dung eac dudng dac bidt Cdttilhiaj,ttongho^dgng giai toan, PTVTH dupc ttie hien: PT BT la ndu rd gia thilt (ylu td da cho) va 42 Tap chi Gido due so 302 * Tniaag Bai kpc U pka* - Bfi kf c ^ai N W i i •(ki2-1/2013) tam giac; ; - Oa gOctam giac, tam giac dlu, higiac, hinh vudng, hinh binh hdnh ; - Oudng trdn:\ie eac dudng trdn hode cung chQa gdc di qua cac diem da cho; ve dudng trdn tilp xuc vdi mdt dudng trdn hode dudng ttidng da cho; ve dudng trdn ndi hode ngogi tiep da giac 3) Mgt so bign phip PT tim cich ve hinh phu thich hgp: • Qua vecac BT da biet: PT gia ttiilt, kit ludn cua BT, tim cae ylu td tuong ddng vdi kiln thde dd cd cua HS de xac djnh hinh phu thich hpp ein ve them, dua BT cin giai quylt v l BT quen ttiupc; • Tao yiu to trung gian: PT kit ludn cila BT, tim mdi lien he giQa gia thilt vdi ylu td tmng gian de tdylu tdtmng gian suy kit ludn; - Bien doi ket kj$n eua BTdua veminh de tuang duang: PT biln dd'i kit ludn cua BT cac mdnh d l tuong duang cd kha ndng gpi hudng ve hinh phy de giai BT; - Dua vio biin doi dai so: PT kit ludn ciia BT, tim mdi lidn he vdi cae djnh li, tinh chat, cdng ttiQc cd lien quan, sau dd lien kit cdc mdi quan he de xac djnh hinh phu cin ve Giai mpt so BT hinh hpc bdng each ve them hinh phu nhdm ren luyen cho HS thao tac tuduy PTVTH Cd nhilu loai hinh phu giai toan hinh hpc ndn vigc ve thdm hinh phu rd't da dang, khdng theo khudn mdu nhd't djnh ndo Do vdy, khdng ed PP chung eho vide ve them hinh phy Mudn vd dupc hinh phy thieti hpp, thuan Ipl cho qud trinh giai toan ddi hdi HS phai liilt dy doan tdt tren co sd cde suy Iugn, ed cdi nhin td'ng quat, bilt nhin nhdn BT mpt each tdng the dudi nhilu khia egnh khae nhau, khai ttiac cac du kign tilm an cde yd'u td da eho cua BT Sau dd, lidn kit mdi quan hg glQa cde ye'u td dd va dua Idi giai, phat triln BT Theo gia thiet, BC ± 0A tgi A nen OA Id khoang each tQtdm de'n ddy BC Oilu hudng cho HS suy nghT: mudn so sanh hai ddy BC va EF edttie su dyng kiln thQc v l khoang each tQtdm de'n ddy eung ttong dudng trdn DQ kien cua BT da cd khoang each tQtdm din ddy BC, chua cd khoang each hi tdm din ddy EF nen HS phai tao yd'u td dd bdng each ke O K I EF(K6EF) Dya vao quan he canh huyen vdi egnh gde vudng tam gide OAK va khoang each tQtdm din ddy, HS de dang suy dupc BC < EF Do dd, dudng vudng gde OK tu O den day EF la dudng phu can ve Ldigikye OK EF (K e EF) Tam giac AOK vudng tgi K, ed OA la canh huyin va OK la mdt canh gde vudng ndn OA > OK Theo djnh li ve khoang each tQ tdm din ddy cung cua dudng trdn suy BC K la tmng die'm cila BC Nd'i BD, DC ta ed tQ giac BDCH la hinh binh hanh (vi cd DC//BB', BD//HC) vd K la tmng diem cila BC => K la tmng did'm cua HD (theo tinh chat ciia hinh binh hanh) ndn OK la duijng tmng binh eua AAHD; >OK=^AHhayAH :20K Tren ddy la mdt sd BT minh hpa eho bidn phdp ren luyen ndng lyc PTVTH cho HS thdng qua eac BT giai bdng PP ve them hinh phy; lam sang td sy van dyng cac bidn phap ve hinh phy ttiich hpp eho mdi BT Odng thdi, nd cung chiimg td vai trd quan bong eua cac ttiao tae tu PTVTH ttong hoat dpng giai toan cua HS Cd PT BT mdi xac djnh dupc cac ylu td da cho, yeu td phai tim, mdi quan he gida (ki2-1/2013) Chung va ttiQ ty cua ede budc giai quylt van d l TH eac kit qua cua PT de hoan ttiien kji giai va phdt trie'n BT ban dau (3) NguySn Ba Kim Phuong phap day hpc mon Toan NXB Dai hpc suphpm, H 20II Tai liSu tham khao Phan.DiJc Chinh (to'ng chu biSn) - TOn Thdn (chu bieii) Todn NXB Gido difc, H 2005 Trong qua trinh giai ede BT hinh hpc, viec ve NguySn Bd Kim - Vucmg Duong Minh - TOn Than ttidm hinh phu khdng nhung giup HS tim dupe \d\ Khuydn khi'ch mdt s6 hoat ddng tri tai ciia hpc sinh glal mdt each dd dang ma cdn dua nhQng ldi giai qua mdn Toan o truong trung hoc co s* NXB Gido hay, ngdn gpn, ddc dao mang tinh sang tgo cao rfuc, H 1999 Cac BT giai bdng PP ve them hinh phu ddi hdi HS BCii V3n Nghj Phuong phap day hpc nhung ndi phai ndm vQng kiln thQc vd cd kT ndng giai todn nhlt dung cu thd mOn Toan NXB bai hoc su pham, H 2008 djnh Oltao dupc mpt hinh phu lien ket tudng minh NguySn Due Tdn Ve them yeu tO' phu de giai mOt mdi quan he toan hpc glQa ode dilu kidn da eho vdi stf bai todn hinh hpc NXB Gido rfucH 2005 dilu klen cin tim, HS phai thye hign ede thao tac tu Bach Phuong Vinh "Khai thac cac bdi todn PTVTH; qua dd, phat trie'n ndng luc tritaigva tu d?y hpc phdn hinh hpc lop nhdm rfen luy$n thao tdc tu phan tich vd tdng hpp cho hpc sinh " Tpp chi khoa hpc eho H S a Gidoduc, thdng 9/2011 •*• SUMMARY (1) Hoang Chiing Phuong phap day hpc to^n hpc d' truiang trung hpc CO stir NXB Gidoduc, H 1997 (2) Hodng Phe (chu bien) Tur di^n tigng Vi|t NXB Dd Ndng vd Trung tdm tudiin hpc Ha NOi - Dd NSng 2000 In this paper, the author presents several analysis measures to find out how to draw more shapes appropriate in order to solved geometry and some geometric problems class solved by method draw more shapes, to train students to manipulate analytical thinking and synthesis Day chien thuat dpc hieu mdt vai djnh hudng trudc ngudi dgy thuc su bdt tay vao thid't k l va su dyng cde CT day hpe doe hid'u vdn ban • (Tief> theo tmng 39) dpc hid'u dy la gi: mpt vdn ban bi "phdn tieh", bj chia nat, rp la viet ve eon ngudi va cudc sd'ng ma ddi chdng cd mpt chut sinh nao - nhu vdy, lam gid vdn cdn ed "chd't van"? GV mudn thj pham mdt CT nao dd de hinh kT ndng "du doan" dpc, lam phong phu them su cam nhdn, coi la co sd de ddnh gia each li giai v l ddi sdng cua nha van, nhung lai chua bao gid tQng tich cue "ddn dau" nhu vdy qua trinh ddc lap dpc hie'u van ban eua minh Neu vdy, hp lam ed the dy doan dupc, lai cang khdng the tien ligu nhQng dudoan phong phu cua HS tinh hud'ng ey the de du djnh phuong an dilu khie'n, dilu chinh eho phu hpp, de ludn ludn ehu dpng mpi tinh hud'ng dgy hpc GV chi ed the day dpe hid'u vdn ban cho HS ban thdn cung la mdt "ddc gia" dung nghTa; bilt "phdn thdn" de quan sat xem minh dang dpc hie'u vdn ban nhu t h i nao, gap khd khdn gi; biet ddt minh vao vj tri HS - nhung dpc gia phat trie'n - de tien lieu eae tinh hudng can thao gd Cd le it nha't dd eung la (ki2-1/2013) (1) Harris, T - Hodges, R The literacy dictionary: The vocabulary of reading and writing DE: International Reading Association, 1995 (2) National Council of Teachers of English, International Reading Association Standards for English Language Arts Urbana.lL:NCTE, 1996 SUMMARY Reading comprehension strategy is a cognitive process carefully led by specific purposes or a processing way to control the reader's effort to decoding and making meaning from text The relationship between strategy and skill is caused and additional As a model of information theory, there are kinds of strategy: cognition metacognlUon and interaction From the study of reader's potraJt strategies are devided into some kinds as follows acting prior knowledge and experiences, predicting, making questions There are two approaches in strategy training, which are to provide direcUy students with basic strategies, and teach students indirectly through problem solving To that, teachers should deride skills into elements which help students observe, identify and practise those skills Tap chi Gido due so 302 45 ... chat, cdng ttiQc cd lien quan, sau dd lien kit cdc mdi quan he de xac djnh hinh phu cin ve Giai mpt so BT hinh hpc bdng each ve them hinh phu nhdm ren luyen cho HS thao tac tuduy PTVTH Cd nhilu loai... di qua cac diem da cho; ve dudng trdn tilp xuc vdi mdt dudng trdn hode dudng ttidng da cho; ve dudng trdn ndi hode ngogi tiep da giac 3) Mgt so bign phip PT tim cich ve hinh phu thich hgp: • Qua. .. 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