[lll!nGIllHIIII,illU;BI[IHllAVJIKHiUOUilIHIIA CHO HOC SIOH TROne DflV HOC HiOH HOC HHflOG GIRO If TRinf RG TRURG HOC PHfi'''' THORG O TS C A O THI H A * atrung hgc phd thdng (THPT), mdn Todn ed mdt vol t[.]
Trang 1[lll!nGIllHIIII,illU;BI[IHllAVJIKHiUOUilIHIIA CHO HOC SIOH TROne DflV HOC HiOH HOC HHflOG GIRO
If TRinf RG TRURG HOC PHfi' THORG
O TS C A O THI H A *
atrung hgc phd thdng (THPT), mdn Todn ed
mdt vol trd quan frgng trong viee thyc hien
cdc myc tieu chung cua gido dye phd
thdng Ben egnh viee hodn thien vd'n kien thuc
cho hgc sinh (HS), mdn Todn cdn gdp phdn vdo
viec phdt triln ndng lye (NL) tri tue, hinh thdnh
cdc NL suy ludn dde frung cuo todn hgc (1; 53)
D l phdt trien fri tue cho HS trong dgy hpc todn,
gido vien (GV) cdn hinh thdnh vd phdt trien cho
HS nhirng hogt ddng tri tue co bdn nhu: phdn
tich, tdng npp, so sdnh, khdi qudt hda, truu tupng
hda ; Kr dd, giup ede em hinh thdnh nhirng NL
tuong ung nhu: NL dgc biet hdo, NL xet tuong ty
vd NL khdi qudt hda, dd Id nhung NL eo bdn vd
quan trpng eua HS
Hinh hpc khdng gian (HHKG) Id mot npi dung
todn hpc khdng ehi cung cd'p nhirng kiln thuc ve
cdc vdt t h i trong khdng gian md cdn tgo co hpi
cho HSphdt trien ede NL tri tue Bdi viet de cdp
v l vd'n de phdt triln mdt so NL tri tu§ ca bdn nhu:
d^c biet hdo, Krong Kr hdo vd khdi qudt hdo cho
HS frong dgy hgc phdn HHKG d THPT
1 Phdt frien NL dgc biet hda cho HS
t)dc bidt hda Id mdt trong cdc NL tri tue quan
trpng cOo HS, giOp ede em nnin nhdn cdc vd'n de
mdt cdch thd'u ddo vd do chieu
6d; todn 1: Cho K> di6n A6CD cd dien tich
tam gide ABC bdng dien tieh tam gide ABD
Chung minh rdng dudng vudng gdc chung cuo
AB vd CD dl quo frung d i l m eua CD
Chung minh: Theo gid thilt, ta cd: S^^^ = S^^
nin CB' = DA' (hai dudng cao tuong t/ng)
(binh /; D l thdy, AC8'A'=ADA'fi'(viehOng d l u
Id cdc tam gide vudng tai A ' v d B") Mdt khde, to
Igi ed CB'= DA'; A'fi'chung
Do dd; CA' = DB' N l u A'khdng trung 6', to
xit h/ dien A'B'CD cd CB'= DA'; CA'= DB' nen
dudng vudng gdc chung eua A'S'vd CD Id dudng
ndi frung diem eua A'B'vd CD, hoy dudng vudng
gdc chung eua AB vd CD di qua trung dilm cOo
CD N l u A'frung 6', kit qud Id hien nhien
Hinh 2
Ode biet hdo bdi todn 1 to cd bdi todn 2
Bdi todn 2: Cho tu dien ABCD cd dien tich
4 mgt b d n g nhau
Chung minh rdng:
a) Dogn thdng ndi
trung diem cdc cdp egnh dd'i Id dogn vudng gdc chung eua ede cgp egnh
dd
b) Tir dien ABCD cd
ede cdp egnh dd'i bdng nhau
Chung minh:
a) Dung C H l A B ;
KDIAB
HC = KD Ggi O, M, N Idn luot Id trung diem HD, CD, HK
To ed: ACHN = A D K N nen NC = ND Do do:
M N l C D (binh 2) Mdt khdc, N O / / K D nen
N O ± A B ; O M / / H C nen O M ± A B , suy ra
M N l A B Vdy, dudng vudng gdc chung cOa AB
vd CD Id dudng thdng M N di quo trung dilm cua CD
Tuong Kr: do S^^ = S ^.Q, suy ra dudng vudng
gdc chung cua AB vd CD ^ q u o trung diem cOa AB
Su dyng gid thiet bdn mdt eua tu dien cd diSn tieh bdng nhau fa dupe d i l u phdi chung minh
b] Gid su M N id dudng vudng gdc chung cua
AB vd CD Khi dd, M, N Idn luot se Id trung dilm euaCDvdABnenNA=NB;NH = NKnenHB=AK, suy ra A C H B = A A K D Vdy, CB = AD Tuong h/, ede cdp egnh ddi cdn Igl eua tu dien cung ddi mgt bdng nhau
2 Phdt frien NL K/ong tu hda cho HS
Ben egnh viec xet cdc trudng hpp dde biet hogc cdc frudng hgp ey the de dua ro cdeh gidi bdi
•
* Khoa TOM, Tnroig B« koc stf pMm - Oai hpc Thai Nfi)i«i
Tap chi Glao due so 3 0 0 (ki a • la/aoia)
Trang 2todn thi ddi khi GV edn hudng ddn HS xet cdc
y l u to Krong K/ cOa bdi todn cdn gidi quyet vdi
cdc bdi todn dd bilt; tu dd, se giup HS ed sy
nhudn nhuyen v l kien thuc, bilt lien Krdng khi
gidi quylt vdn de vd d l ddng tim ro cdch gidi
bdi todn
6d/ todn 3: Trong tam gide ABC vudng tgi A,
d u d n g eao AH c d : / ; fiC^ = AB^ + AC;
2)^'-^*^; 3) AS' = 6H.8C; 4)A?C= CH.CB
Nhu to dd biet, tuong ty vdi viec xet mdt
tam gide trong mdt phdng Id viee xet tu dien
trong khdng gian, frong dd, egnh cuo tam gide
tuong ty vdi mdt eua tu dien, dudng coo cuo
tam gide tuong ty vdi dudng thdng vudng gdc
K> mdt dinh cOo tu dien den mdt ddi dien (dudng
cao cua tu dien)
Vdy, vd'n d l ddt ro Id khi xet mdt tu dien vudng
SA6C, vudng tai S, cd nhirng hS thuc ndo giua
cdc mdt cua tu diSn vudng
cung nhu mdi lien he giua
dudng cao vd cdc egnh eua
tir di^n dd HS ed the xet cdc
tinh chd't tinh tuong ty bdng
cdeh khoi thdc tu he thuc
lupng trong tam gide vudng
vd dua ro dy dodn: Trong
mdt tu diin vudng SABC,
ta cd: 1) 5;,„ = s\,,„ + 5i„ + s\„.;
21 '.JL.- J-:.-L
Chung minh: 1) Gid su SH 1 (ABC) tgi H, suy
ra H Id trye tdm eua tam gide ABC nen A^ ± BC
kji M Ta ed: SM 1 BC (theo djnh li ba dudng
vudng gdc); s^,„ =-.-IM.BC; S^^ = S.\i.BC;
•5.u(«-=r'^'^'^C Mdt khdc, trong tam gide
vudng SAM ed SM' = HM.AM (binh 4), suy ro:
Hinh 3
3 Phdt frien NL khdi qudt hda cho HS Ben egnh NL tuong ty hda vd dde biet hda,
NL khdi qudt hdo cOng Id mdt trong cdc NL tri Kje
CO bdn cOa HS NL ndy khdng nhirng giup HS nhin nhdn vd'n de mpt cdch cd he thd'ng md cdn
Id mdt trong cdc tien de de cdc em phdt triln NL sdng too Do vdy, trong dgy hoc, GV nen thudng xuyen tap luyen cho HS khd ndng khdi qud hdo bdi todn tu bdi todn dd cho (trong nhirng trudng hop ed the)
6d/ todn 4: Trong mdt phdng cho gdc xOy,
dudng thdng d thay ddi ludn di qua mdt dilm I
CO djnh thupc miln trong cuo gdc vd cdt cdc tia
Ox, Oy Idn luot tgi M, N Qua I ke dudng thdng song song vdi Ox cdt
Oy tgi E vd ke dudng
thdng song song vdi J'
Oy cdt Ox tgi D Ddt v_ _ "'
IE = a, ID = b Chung j minh r a n g : Khai quat hoa Hinh 4 bdi todn ndy bdng cdch md rdng vdo khdng gian, ta ed bdi todn sou:
8d/ todn 5: Cho hinh chop S.ABCD, ggi O
Id giao diem cOa ede dudng cheo AC vd BD, I
Id dilm cd djnh tren SO Mat phdng (P) thay dd'i ludn di qua I cdt cdc
egnh ben SA, SB, SC, SD Idn lugt tgi M, N, P, Q
Chung minh rdng tdn tgi bdn dogn thdng m, n, p,
q xde dinh
5A/ SN SP SC
Chung minh: Ap dyng
kef qud cua bdi todn 4 dd'i
vdi mdt phdng (SAC), to ed: Ggi m, p theo thu ty Id dp ddi hoi egnh cOo
sao cho:
• - A
><
Hinh 5
(binh 5)
Xet mdt phdng (SBD),ta Igi ed: ^ + ^ = i (2)
4 4
Tuong t y , ta c d : S „ „ 5 ^ „ ^ = ( 5 ^ , « j ' ( 2 )
5««'-5^«' =(5^v,- )S- (3)- TO (1), (2) vd (3), suy
ra: (5„«,.)- = (5^«,)= -••(5^«,.)= - H ( 5 ^ « J
HS eOng d l ddng chung minh dupe he thuc d
cdu 2
Tap chi Glao due s6 3 0 0 (ki a • la/aoiai
TO (1) vd (2), suy ra: ^ • * - ^ + # + ^ = - •
• « •
Nhu vdy, NL dde biet hda, td'ng qudt hda, hiong
(Xem tiip trang 42)
Trang 3Sou khi dd xdy dyng xong ndi dung bdi gidng
cd su dyng SDTD, chiing ta thyc hien cdc lien kit
(hyperlink) len cdc dd'i tupng trong bdi gidng
Ddy Id uu dilm ndi bdt, cdn khoi thdc tdi da cdc
khd ndng lien kit Nhd cd khd ndng lien kit ndy
md bdi gidng dupe td chirc mpt cdch linh hopt,
thdng hn dupe truy xud't kjp thdi, HS d i tilp thu
kiln thuc
Budc 6: Sua chOa vd hodn thien SDTD Sou
khi dd thilt k l xong SDTD, GV edn tiln hdnh kiem
tro ede soi sdt, dde biet Id cdc lien kit de sua
chOa vd hodn thien SDTD
V(' du: Dudi ddy, chung tdi xdy dyng SDTD
bdi: «Axetilen" (Hod hpc 9)
3 Thyc tiin DH d cdc trudng phd thdng dd
cho thdy, viee si> dyng SDTD trong nhd trudng
dd ndng eao hieu qud day vd hpc Ode biet,
SDTD giup HS hpc tap mdt cdch chu ddng, tieh
eye, huy ddng dupe tdt ed HS tham gia xdy dyng
bdi, ren luyen tu duy sdng too vd khd ndng ty
hpc cho cdc em Su dyng SDTD edn ed the phdt
triln cho HS cdc ndng Tyc nhu: biet he thing
hda kiin thuc (huy ddng nhirng kiln thuc dd hpc
trude dd), khd ndng hdi boa (hinh thirc trinh bdy,
kit hpp hinh ve, chu viet, mdu sdc) Viec van
dyng SDTD trong DH se ddn hinh thdnh cho HS
tu duy mpch Ipe, hieu vd'n de mdt cdch sdu sdc,
cd he thd'ng vd khoa hpc Su dyng SDTD kit
hop vol cdc PPDH tich cue nhdm gdp phdn dd'i
mdi PPDH
Tuy nhien, khdng phdi bdt cu npi dung ndo,
bdi hpe ndo cung ed t h i diing SDTD SDTD Id
mdt phuong Hen DH nen cOng nhu vdi ede phuong
Hen khdc, de phdt huy dupe tdi da tinh uu viSt eua nd, cdn su dyng dung luc, phO hpp vdi npi dung h/ng don vj kien thuc vd quan trpng nhd't Id phii hpp vdi ddi tupng HS; ddng thdi, ddm bdo
ho trp tdi da cho viec truyen tdi ndi dung bdi hpc De dpt dupe dieu ndy, GV cdn linh hopt, mem deo, kheo leo kit hpp SDTD vdi ede phuong
Hen DH khde d
Tai lieu tham khao
1 Bernd Meier - Nguy4n Van Cuong Li lu$n day
hoc day hpc hien dai, tai lieu hue t$p ddi mdi phuong
phap day hpc NXB D(ii li<?c siepliam, H 2009
2 Nguyen Cuong - Nguyfin Manh Dung - NguySn
Thj Si/u Phinmg phap daiy hpc hod hpc, tap I NXB
Gido due H 2000
3 Gia Linh Huong din sur dyng ban dd tuduy NXB
Tir dien Bdeh klioa, H 2007
4 Phan Trpng Ngp Day hpc va phmmg phiip day
hpc trong nha tnimig NXB Dai lipe supliam, H 2005
5 NguyOn Thj SOu Chuyin di: Ndng eao tinh tich
cite niidn thirc cua iipc sinh thdng qua gidng d^y hda liQC d tnn'mg pltd thdng
6 Tony Buzan Sirdung tri tu£ cua ban (bien djeh Le
Huy Lam) NXB Tong hop TP HS CM Minh, 2007
SUMMARY
Confirming the important role by thinking diagram
in teach Chemistry, the author has presented Some how to use the mind map Unit selection principles chemistry application diagram thinking And Con-stnjcfion process mind map in teaching chemistry with
an aim to entioncing effectiveness of Chemistry teach-ing in upper secondary schools
Pliat trien nang iirc
(Tiip theo trang 33)
\\f hdo khdng chi giup HS nhanh nhoy trong qud
hinh gidi todn md edn giiip cdc em phdt hien vd de
xudt cdc bdi loan tndi, thdy dupe sy lien he giOa
cdc vd'n de vol nhau Nho nhung NL dd, HS ed thi
md rpng, ddo sdu kiln thiic bdng cdeh gidi quyet
cdc vd'n de tdng qudt, vd'n de tuong hr hope di sdu
vdo xet hxrdng hop dde biet, dd chinh Id con dudng
cOa sy sdng too Mgi phdt minh khoa hoc, du cd
dgc ddo den ddu cung deu bdt nguin tir cdi cu vd
bao gid cung Id su md rdng eua cdi cu Tap dugt
md rdng chinh Id tap dugt phdt minh Id mgt trong
cdc yiu to di phdt Iriin tu duy sdng too (2)
(I) NguySn Ba Kim Phucmg phdp dsiy hpc mOn Todn
NXB D<?i hpc sirph^m H 2004
#
(2) Nguyen Canh Toan Phmmg phap luan duy v^t
bi£n chiing vdi viic hpc, day vd nghi£n cihi todn hpc, tap 1 NXB Dai hoc qud'e gia H 1997
SUMMARY
Specialization, similazatlon and Generalezation are very important capacities of each people The goal of teaching mathematics in high schools is not only contribute to improving the mathematic cul-tural for high school students, but also contribute sign'ificatly to the development of intellectual capac-ity, forming the ability to infer characteristics of the mattiematic^s necessary for life Th lerefore, the teach-ing of tviathematics in general and teachteach-ing in par-ticular need space to create favorable conditions for learners perform basic intellectual activities such
as analysis, synthesis, comparison, generalization, ob-straction, thus helping them to formulate the corre-sponding capacity
Tap chi Giao due so 3 0 0 (kt a la/aoia)