Đang tải... (xem toàn văn)
BQl DUONG NANG llfC HUY DUNG KIEN THUG CUA HUG SINH THDNG QUA DAY HDC GIAI TDAN fi TBUllNG TRUNG HDC PHO THDNG VnS PHI VAN THUY* Theo G Polya Tatca nhdng ttilieu, yeu td''''phu, cac dinh li nay laytudau?[.]
BQl DUONG NANG llfC HUY DUNG KIEN THUG CUA HUG SINH THDNG QUA DAY HDC GIAI TDANfiTBUllNG TRUNG HDC PHO THDNG VnS PHI VAN THUY* T heo G Polya: Tatca nhdng ttilieu, yeu td'phu, Vi du Tmng mat phang Oxy, cho dudng cac dinh li laytudau?NgU(^'giai da tich trdn {C):{x~2)'+iy + 2)'=A va dudng thing luy dugc nhung tri Siuc ay tri nhd, gidday d :3x - 4y + m-7 = Tim m detren d co nhit njtra va van dungmgtcach thich hgp degiaibaitoan, mdtdiem M mabiddliedugchalMptuyen MA.MB chung ta ggi viec nhd lai co chgn Igc cac tri thuc nhu vay la suhuy dgng ideh thdc (HDKT)"{1; tr 218) tdi (C) (A Bia cac ti^ diem) cho goc AMB bang Hien nay, viec boi dudng nang lue HDKT 120' Thuc te, nhieu HS se rat khd khan viec tim day hpc toan di cacttudngtmng hpc phd'thdng chua dupc quan tam mot each ehi tiet, dung mdc, cd he hudng giai bai toan tren vi khdng biet giai quydt tinh nhat cua diem Afva gdc ^^fd bang 120° nhu tfid'ng, hpe sinh (HS) cdn g ^ mdtso kho khan vise phat hien each giai quyet van de Day toan khdng the nao Giao vien {G V) ed the din dat cho HS HDKT dd' chl dan ttiuan la day kien thdc macdn day cho HS biet each HDKT cho phii hpp de ddng tmdc mot giainhusau: Cach /;Tdgiatiietdebaieho,caeem cdthesuy van de toan hpc, cac em cd the biet each lira chpn tri tide phli hpp va diing d ^ Do dd, bai viet coging dieu gi? Neu HS van cdn khd khan, chua dua lam sang tdmptsd'phuang tide boi dudng nang luc cau tra Idi, GV tiepttJCgoi y ttiem eho den HS ba HDKT, dongttidicung lam sang totiiem y nghTa khac Idi dupe: ciia viec bien ddl bai toan Dudng trdn (C) cd tam l(2;'3}va ban kinh R=2 Tacd; Trong quatrinh giai mdtbaitoan cu ttienao dd, le duong nhien khdng can tiuydongden mpi kien thdc ma HS dattiuthap, tieh luy dupe td tn/de Can huy cos30° -JS -1^^^' "VJl dpng d ^ nhiing kienttiiicnao, can xem xet den nhung Den day, em md'i lien he nao, roi sudung chiing de quy (^ ve quen naocdtiephatbilj nhd bien ddl doi tuc^g, dudoan van de, chuyen doi ngdn ngu ti* dd, HS giai quyet dupe bai toan G laibaitoan?Cauhdi cd le cdn khd Polya vi Vua trinh giai mot bai toan cung giong nhu i vdi nhieu HS xay nha Dau tien phai thu Mp vat lieu, nhOng vatdd' lieu ay khdng theh/nd trd^nh ngdi nha, diy chili dong GV tiep tuc goi y: di.Bexiyduaccannhihaygiaiduacbaitoin.dong Tim diem, Mtiupc &idiphai sip xep cac bd phin vi to chdc tap hgp dudngttiangcfphai chung lai toin bo Day la dieu ta edging lamtida man diiu kien gi?MongdpiHStra dt/pc'(i;tt218) ldi diem Mduynhat Nang luc HSKT de bien doi bai toan ve dang quen thupc vattidaman dieu kien IM=-j^ Bay gidem nao cd Trade giai mdt bai loan, chiing ta chua tie biet dupc sesudyng nhiing kien tide nao tdnhung tid'phat biaj lai bai toan? bai toan cdttiuatgiai xac dinh hoac da t^idtldigiai nao HivpngHStraldinhusau: Trong matphing toa dd tuang tunhutie Do dd, degiai quyetdupe van de dat ra,chLingtanhatttiietphaibietcaeh dua vao nhung Oxy cho dudng thing d:'ix-4y-\-m-l = va kien tl dccu,nhungcai da bietttudcdddebien ddl bai loan vedang quenttiudc,ching han: * TniangTniDg boc pkd tlwag U Hing Phong, TF Bien H6a, 06ng Nai 44 Tap chi Giao dye so 363 (ki 1-8/2015) Cac/;2.GVtiepttJcdateauh6ichoHSHDKTde *sm /(2;-3) Timmcetrindudngthangdcoduy tt'm eae each giai khac Khidd, batbudc HS phai nhalmolOem Msao cho l(hoang each tuiie'm /den huy ddng den nhieu kienttidclien quan den baitoan: , Neu HS chua huy dpng dupe kien tide de giai duang thing dbang -jr cacti khac, GV goi y nhu sau: each 1, ta bien doi bai toan da eho ve bai toan Trong hai dieu l0 ,, 20,^ m = - l IH m = -\ V3 3 Thong qua cac each giai tren, HS biet each suy luan logk: de huy dpng dupc kien thuc ve he thdc lUdng tam giac vuong, khoang each giQa hai diem, doi xung tam, khoang each td mpt diem den dudng thang, dudng trdn, giae cija dudng thang va dudng trpn T d dd, HS duoc boi dudng nang liic HDKT de bien doi bai loan Cac/! ^.'GVkhongtheddngdcach giai tren duoc vl thi/c te CO nhieu bai toan khong ddn thuan glal bftig each bien doi tuong duong nhutren Do do, GV phai dat cau hdi dan datHS biet each HDKT de dudoan, tim tdicac each giai khac nhau, c h i n g han: Cac em each giai nao khac khong? ChSc chin HS chua cd cau tra ldi Em hay quan sat bat ding thdc can phai chiing minh co gi dac biet? Ta hi vpng HS phat hien ra: 46 Tap chi Gido due so 363 (hi 1-812015) J^- + + V j c " * » + < * - I ) ' + l*-y