DAY HOC KHAM PHA CAC BAI TOAN TiM TAP HOP flIEM \6l sir TRd GltJP CUA PHAN MEM CABRI ThS NGUYEN N G Q C G I A N G * Day hpc kham pha (KP) la phuong phap day hoc (PPDH) phat huy tinh tieh cue cua hpc s[.]
DAY HOC KHAM PHA CAC BAI TOAN TiM TAP HOP flIEM \6l sir TRd GltJP CUA PHAN MEM CABRI ThS N G U Y E N N G Q C G I A N G * D ay hpc kham pha (KP) la phuong phap day hoc (PPDH) phat huy tinh tieh cue cua hpc sinh (HS) Bai bao de xuat quy trinh d?y hpc KP cd ung dung phan mem Cabri day hpc giai eae bai toan (BT) tim tap hpp diem nham gdp phan hinh vaphattrien tuduy thuat toan, tuduy sang tao eho HS I.Day hpc kham pha KP cd the hieu la qua trinh hoat ddng va tu bao gom: quan sat, phan tich, nhan djnh, danh gia, neu gia thiet, suy luan, nhim dua nhung khai niem, phat hien cae tinh chat, quy luat va md'i lien he giua chung Theo (1),Bruner cho rang, qua trinh KP xay eae ea nhan phai tuduy de phat hien ban chat va y nghia cua mot van de nao Trong day hpc KP, ngudi hpe phai kethpp vdiquan sat de njt ket luan G V can ehuyen tai cac thdng tin, lua ehpn PPDH phu hpp vdi kien thu'c cung nhu nang luc cua HS Cac giao trinh can dupe xay dung theo hinh xoin de de HS dupc KP kien thdc mdi dua tren nhung kien thuc da hpc Tuy nhien, khdng phai HS tu KP tat ca cae kien thue mdi ma cae em KP su lien quan giua cac y tudng dua tren nhdng kien thuc da hpc Quy trinh s u dung phan mem Cabri day hoc giai toan tim tap hqp diem d thong theoPPDHKP Phan mem Cabri la ket qua nghien cuu eua Tmng tam nghien cuu khoa hpc qude gia - Tardng Oai hpe td'ng hc^ Joseph Fourier Grenoble (Phap), cd cae ehuc nang nhu: ve, dung mot hinh hinh hpe bat ki mat ph^ng, ngucri dung ed the thuc tii?n cac thao tac "keo", 'Iha", "an", "hi^n", de the hi?n hinh ve dudi nhieu gde dp khac Phan mem Cabri cung ed cac cdng cu de tinh toan, kiem tra thudc tinh cua cac ddi tupng hinh hpe mdt each tn/c quan, eho phep ket hpp gi(?a hinh hpc td'ng hop va hinh hpc giai tieh giai toan Cac budc tien hanh dng dung Cabri giai eae BT tim tap hc^ diem nhu sau: -Bude 1:Dmghinh.D\sng hinh theo yeu eau cua 52 Tqp chl Gido due so 316 BT Cdthe ket hpp vdi nut l§nh Intenupteurcho hinh xuat hidn theo trinh tu - Bude 2: Tim quy tich Tao vet cflo di§'m can tim tap hop diem, ehuyen d^ng "diem chuyen ddng' ma gia thid't BT da eho, ta thu dupc dang cua tap hop diem - Budc 3: Chdng minh T u hinh dgng cua t?p hop diem, ta tim Idi giai cua BT V i d u minh hoa Vidu 1: Cho tam giac ABC npi tiep dudng trdn (0), edeanh BC cd'djnh Gpi G ta giao di^m cua ba dudng tnjng tuye'n Tim quy tich diem G A ehuyen dpng tren dudng trdn (0) G V dat cau hoi: Em hay dung hinh va tim quy tich cua diem G di&n A thay da tren phan mem Cabri? ' Bude 1: Dung hinh: • Dung dudng trdn tam ; - Dung day cung BC tren dudng tnin (0); - Dung diem A tren dudng trdn nay; • Dung tam giac ABC; - G pi G la giao diem cua ba dudng tnjng tuyen; - An di cac dudng khong can thiet Hinh {hinh 1) ' Budc 2: Tim quy tich Tao vet cho diem G, chuyen dpng diem A, ta fiiu i\sqc vet eua diem G cd dang la mdt dUdng trdn ' Bude 3: Chung minh G V dat cau hoi: Em hay ehung minh ket qua du doan ve quy tich cua BTtfen phan mem Cabri? ' Phan thuan:Q^t R ia ban kinh dudng trdn (0) Gpi M la trung d^m cua BC; G latnpng tam cua giac ABC (la glao diem cua ba dudng trung tuyen), G n^m gitJa A va U cho GA = 2GM Lay diem I nSm giOa va M cho 10 = 2!M, ta ed IG//OC (dinh li Ta-let dao), suy ra:ã R OA MO '229/85 T1iichQuai]S&iiô-PhirÊRig4-Qiian K l i N l w ^ - m H d CM M^^ -(ki2-8/2013) hay I G = J vaG Ihudc dudng lm['-j]{hinh2i G(iiB,,C,lacacgiaodlem cua AB vdi I ' : y I Ihiquytich diem G la dddng trdn [ i ^ y l *Budc3: Chdng minh GV d^t c&u hdi: Em hay chdng minh ket qua du doan tren phan mem Cabrivequytieh? • Phan thu$n: Xet trudng ^ hopAch?ytrencungldnBC, ' cd BCA = a Gpi I lagiaodie'm eua ba dudng phan giac cua tam giac ABC Theo tinh ehat gde ngoai eua tam glae, ta ed {hinh 5): lid hai die'm B,,C, ', -Phan dio.'Lay die'm G' s ( i ; j J cho G' l Femp(SBD) => F la diem chung cua mat phang (MAB) va SBD) T d d d suy B, E, F thang hang Thdng qua mdt so bai tap toan hinh hpc khdng gian dtrung hpc phd'thdng, G V cd tiie hudng dlii HS kham pharanhdngBT mdi td cae BT ban dau; t^ora ChP cae em nhung cam giac mdi la va hdng thu hpe tap Tudd, nang cao susay me nghien cdU khoa hpe, dieu ma vd'n di ludn can thiet dd'i vdi HS, • Tdi li^u t h a m k h a o G Polya S a n g tao todn hoc NXB Gido di^c, H 1978 D^o Tam (chu bi£n) Gido trinh hinh hpc soclfp NXB Dal hoc suphgm, H 2004 D o i n QuJ-nh (tfing chu bifin) - Van Nhu Cuong (chii bien) Hinh hpc 11 nfing cao NXB Gido dvc, H 2006 SUMMARY CreaUve thinkingis a necessaiycapabllifyforall of people, in every jobs In mathematic teaching, creative thinking capacity building for the pupils Is very Important for a teacher And in geometry of space teaching, there are many conditions to help the pupils training creative thinking This article mention some examples of creative thinking capacity for students training through the creation ofnewproblems (I) Le v o Bmh D