Thiết kế bài giảng hình học 12 (tập 1) phần 1

^ w -•^••^^^^ ' ^ W.V-' TRAN V I N H I hiet ke bai giang HlNH HQC]2 TAP MOT NHA X U A T B A N H A N I TRAN VINH THIET KE BAI GIANG HINH HOC 12 TAPMOT NHA XUAT BAN HA NOI LCll NOI DAU Chifcfng trinh thay sach gan lien vdi viec do! moi phiidng phap day hoc, c6 viec thifc hien ddi mcfi pbifdng phap day hoc mon Toan Bo sach Thiei kebdi gidng Hinh hpc 12 dcrt de phuc vu viec ddi mcfi Bp sacb difdc bien scan difa tren cac chifcfng, muc cua bo sach giao khoa (SGK), bam sat noi dung SGK, tii hinh nen cau tnic mot bai giang theo chifcfng trinh mdi difcfc viet theo quan diem boat dong va muc tieu giang day la: Lay hoc sinh lam trung tam va tich cifc suf dung cac phifcfng tien day hoc hien dai Phan Hinh hoc gom tap Tap 1: gom cac chifcfng I va mot phan chifcfng II Tdp : gom phan lai cua Chifcfng II va chifcfng III Trong moi bai scan, tac gia co 6\ia cac cau hoi va tinh hudng thu vj Ve boat dong day va hoc, chiing toi cd gang chia lam phan: Phan boat dong cua giao viSn (GV) va pban boat dong cua hoc sinh (HS), cf moi phan c6 cac cau hoi chi tiet va hifcfng dan tra ldi Thifc hien xong moi boat dong, la da thifc hien xong mpt dcfn vi kien thufc hoac cung cd dcfn vi kie'n thifc Sau m6i bai hpc chiing toi CO difa vac phan cau hoi trac nghiem khach quan nham de hpc sinh tif danh gia difcfc miifc dp nhan thifc va mifc dp tiep thu kien thufc cua minh Phan hinh ve, cac tac gia cd gang sifu tam nhifng hinh anh thifc te co gan lien vdi lich suf toan hpc chifcfng trinh Hinh hpc 12 nhif cac hinh da dien deu, Day la nhuhg hinh ma iing dung bai giang se gay nhieu hiing thii hpc tap cua hpc sinh Day la bp sach bay, dufcfc tap the tac gia bien soan cong phu, lihg dung mpt sd tifU khoa hpc nhat dinb tinh toan va day hpc Chiing toi hy vpng dap ufng difcfc nhu cau cua giao vi6n toan viec ddi mdi phifcfng phap day hpc Trong qua trinb bien soan, khong the tranh khoi nhOhg sai sot, mong ban dpc ram thong va chia se Chiing toi chan cam cfn sif gop y cua cac ban Hd Noi thdng ndm 2008 Tac gia ChirONq KHOI DA mix Phan Gidl THltu CHLfdNG I CAU TAO CHUDNG §1 Khdi niem \6 khdi da didn §2 Khdi da dien Idi va khdi da dien deu §3 Khai nidm ve the tich khdi da dien On tap chuong I Muc dich cua chuong • Chuong I nham cung ca'p cho hoc sinh nhCing kie'n thiic co ban v6 khai niem cac khdi da di6n kh6ng gian, chu yeu la cac da dien Idi: Khdi da dien, khdi chop Khai ni6m ve hinh da dien, khdi da dien Hai da dien bang la gi ? - Cac chia va ghep cac khdi da dien • Gidi thi6u ve khdi da di6n ldi va khdi da di6n deu • The tfch ciia khdi da dien: Khai niem v^ th^ tfch khdi da dien Khai ni6m va cong thiJc th^ tfch khdi da dien The tfch khdi lang tru Thi tfch khdi chop I I - MUC TIEU Kie'n thurc Nam duoc toan bo kie'n thiic co ban chuong da neu tren Hieu cac khai niem va tfnh chat ciia khdi da dien " Hieu ve each thiic xay dung the tfch mot sd khdi da dien Hi6u dugc khdi da dien ldi KT nang Phan biet dugc khdi da dien Tfnh dugc the tfch cua hinh lang tru, hinh chdp - Chiing minh dugc hai mat phang vuong gdc Thai Hgc xong chuong hgc sinh se lien he dugc vdi nhi6u va'n de thuc te sinh dgng, lien he dugc vdi nhiing van de hinh hgc da hgc b Idp dudi, md mgt each nhin mdi ve hinh hgc Tix 66, cac em cd the tu minh sang tao nhiing bai toan hoac nhirng dang toan mdi Ke't ludn Khi hgc xong chuong hgc sinh can lam tdt cac bai tap sach giao khoa va lam dugc cac bai kiem tra chuong P h a u 2> ckc BAI SOAN §1 Khai niem khoi da dien (tiet 1, 2, 3) I MUC TifU Kien thurc HS nam dugc: Khai niem khdi da di6n khdng gian Hi^u va van dung tinh th^ tich khdi lang tru va khdi chop Khai niem \i hinh da di6n \h khdi da di^a Kl ndng • Ve thao cac khdi da difin don gian • van dung thao mdt sd phep bi6i hinh : Ddi xumg tam, ddi xiing true • Phan chia va ghep thao khdi da didn Th^i • Lien h6 dugc vdi nhi^u vah 6i thuc te khdng gian • Cd nhi^u sang tao hinh hgc • Humg thu hgc tap, tfch cue phat huy tfnh ddc lap hgc tap n CHUAN BI CUA G V VA H& Chu^nbicua GV: • Hinh ve 1.1 d^n 1.14 • Thudc ke, pha'n mau, Chuan bj cua HS : Dgc bai trudc d nha, cd the lien he cac phep bien hinh da hgc d ldp dudi in PHAN PHOI THC5I LUONG Bdi dugc chia thdnh tie't: Tie't 1: Tir dau de'n bet muc phan II Tie't 2: Tie'p theo de'n bet phan III Tie't 3: Tie'p theo den bet phan IV va phan bai tap IV TIEN TBlNH DAY HOC n f>^J VAN DC Cau hdi Nhac lai khai niem hinh hop, hinh chdp Cau hoi Cho hinh hop ABCDA'B c u a) Hay xac dinh cac mat cua hinh hop b) Hay xac dinh cac dinh va cac canh ciia hinh hop a RM MOI • Thuc hien A l phiit Hoat dgng cua GV Cdu hoi I Hoat dgng ciia HS Ggi y trd loi cdu hoi I Nhac lai dinh nghia hinh lang tru HS tu neu Neu mgt sd vf du Cdu hoi Ggi ytrd loi cdu hoi Nhac lai dinh nghla hinh chdp HS tu neu Neu mgt sd vi du HOATDONCI I K H I LANG TRU VA K H I CHOP GV neu cau hoi : HI Khdi rubic cd bao nhieu mat? H2 Mdi mat ciia khdi rubic la hinh gi? • GV six dung hinh 1.2 SGK va dat van d6: H3 Hay dgc ten cac khdi chdp d hinh 1.2 H4 Hay ke ten cac mat cua hinh 1.2 H5 Hay ke ten cac mat day cua hinh 1.2 H6 Cac canh ben ciia hinh lang tru cd quan h6 vdi nhu the nao? H7 Neu mgt sd hinh anh thuc te ve hinh lang tru va hinh chdp nOATDONG2 n KHAI NifiM Wt HINH DA DifiN VA KHOI DA DI£N Khai niem ve hinh da di^n Stt dung hinh 1.4 • Thuc hien A phut Hoat dong ciia GV Cdu hoi I Hoat dpng cua HS Ggi y trd l&i cdu hoi I Hay ke ten mat day ciia hinh lang Do la cac hinh da giac tm ABCDE.A'B'C'D'E' ABODE va A'B'C'D'E' Cdu hoi Ggi y trd loi cdu hoi Hay k^ ten mat day ciia hinh Do la hinh da giac ABODE chdp S.ABCDE • GV dat cac cau hoi sau : H8 Trong hinh 1.4 hinh lang tru cd nhOng da giac nao? H9 Trong hinh 1.4 hinh chdp cd nhung da giac nao? HIO Cac da giac cua cac hinh tren quan he vdi nhu the nao? • GV neu tfnh chat: a) Hai da gidc phdn biet chi cd the : Hoac khdng cd diem chung hoac cd mdt cgnh chung b) Mdi cgnh ciia da gidc ndo cUng Id cgnh chung cOa dUng hai da gidc • GV n6u dinh nghia hinh da dien: Hinh da dien Id hinh dugc tgo bdi cdc da gidc thda mdn tinh chdt tren H l l Hay ndu mdt sd vf du v^ hinh da didn HI2 Hay k^ ten hinh da diSn cd cac da giac bang H14 Trong hinh 1.5 em hay k^ tdn cac day ciia hinh da didn Khai niem ve khdi da di^n • GV ndu dinh nghla : Khdi da dien Id phdn khdng gian dugc gidi hgn bdi hinh da dien, ke cd hinh da dien dd • GV cd th^ lay mdt hinh da didn, bo bdt di mdt sd mat va hoi: H15 Hinh viia nhan dugc cd phai khdi da didn hay khdng? • GV ndu cac khai nidm : HI6 Di^m ciia khdi da didn la gi? HI7 Di^m ngoai cua khdi da didn la gi? H18 Cd di^m nao khdng la di^m cung khdng la di^m ngoai ciia khdi da didn H19 Mi6n ciia khdi da didn la gi? H20 Mien ngoai ciia khdi da didn la gi? H21 Mdt dudng thang cd th^ nam trgn d mi^n nao ciia khdi da didn? H22 Hay ke tdn mdt sd hinh khdng phai la khdi da didn 10 • Thuc hidn ^ phiit Hoat ddng ciia HS Hoat dgng ciia GV Cdu hoi I Ggi y trd loi cdu hoi I Hinh 1.8c cd vi pham tfnh chat Vi pham tfnh chat a nao khdng ? ABODE va A'B'C'D'E' Cdu hoi Ggi y trd led cdu hoi Giai thfch vi hinh 18c khdng GV cho HS phat bi^u va kdt luAn phai la khdi da dien HOATDONC HL HAI DA DifeN BANG NHAU Phep ddi hinh khong gian • GV ndu dinh nghia: Trong khdng gian, quy tdc dgt tuang Ang mdi diem M vdi nhdt mat diem M' dugc ggi Id phep bie'n hinh khdng gian Phep bien hinh khdng gian la phep ddi hinh neu nd bdo todn khodng cdch • GV ndu mdt sd phep ddi hinh thudng gap khdng gian a) Phep tinh tien theo vecta v Phep tinh tien theo vecta v Id phep bien hinh bien M thdnh M' md MM' = v H22 Hay chiing minh phep tinh tien theo vecto v la phep ddi hinh b) Phep ddi xicng qua mat phdng (P) • GV sit dung hinh 1.10b va ndu khai nidm: 11 Cdu hdi Ggi y trd ldi cdu hdi Tfnh SA, tuf dd suy dai cua SA = AH : cosdO" = ^ ^ cac canh bdn Cac canh ben cd dai bing va ^ bang Cdu hdi Tfnh SD 2aV3 — ^ Ggi y trd ldi cdu hdi Ta cd AD = AB.cosSAB -a.- a 2a V3 aV3 Tit dd ta cd SD = SA-AD: 2aV3 aV3 _ 5a^ 12 Cdu hdi Ggi y trd ldi cdu hdi Tfnh ti sd hai the tfch Ta cd SA _ 2aV3 12 ^ S D " "5373" caub Hoat ddng cua HS Hoat ddng ciia GV Cdu hdi TfnhSH Cdu hdi Ggi y trd ldi cdu hdi I SH = AH.tandO" = — Ggi y trd ldi cdu hdi Tfnh thd tfch hinh chdp S.ABC 12 89 Cdu hdi Ggi y trd ldi cdu hdi Tfnh thd tfch hinh chdp S.SBC V' = V3 96 Bai Hudng ddn Six dung tfnh chit hinh chieu khdng gian Cdng thiic tfnh thd tfch S Ke SH ± mp(ABC), HE AB, HF BC va HJ AC Hoat ddng cua GV Cdu hdi I Hoat ddng cua HS Ggi y trd ldi cdu hdi I Em cd nhan xet gi vd SE, SF va Vi cac gdc SEH,SFH, SJH bing SJ nen : SE = SF = SJ Cdu hdi Goi y trd ldi cdu hdi Tfnh chu vi tam giac ABC Chu vi tam giac ABC la : 18a; nita chu vi la 9a Cdu hdi Ggi y trd loi cdu hdi Tfnh HE ^AABC ^ P-HE Ta cd p = 9a, S^^gc - 6V6a rr^v « ITT: ^AABC 2a\/6a Tu ta CO : HE = = P 90 Ggi y trd ldi cdu hdi Cdu hdi Tfnh SH Ta cd SH = HE tandO" = 2V2a Cdu hdi Ggi y trd ldi cdu hdi TfnhV V = 8V3a^ Bai Hudng ddn Six dung tfnh cha't hinh chie'u khdng gian Cdng thiic tfnh thd tfch s Ke SH mp(ABC), HE AB, HF BC va HJ AC Hoat ddng ciia GV Cdu hdi I Cdu hdi Tfnh SB va SB' Hoat ddng cua HS Ggi y trd ldi cdu hdi V= -abc Ggi y trd ldi cdu hdi Ta cd SA^ = SB'.SB hay SB' = SB Tacd SB = Va^+c^ Tit dd t a c d : c2 SB'- Va2+c2 91 Cdu hdi Ggi y trd ldi cdu hdi Tinh SD va SD' Tuong tu ta cd : SB = Vb2+c2 Cdu hdi SB' = - ^ = ^ = = Vc + D Ggi y trd ldi cdu hdi Tfnh SC va S C SC ± A C SC = Va^+b^+c^ ; c2 SC - Va2+b2+c2 Ggi y trd ldi cdu hdi Cdu hdi Tfnh thd SAB'C'D' tfch khdi chdp Tacd %AB'CD) V SA.SB'.SC'.SD' SA.SB.SC.SD Tii dd ta tfnh dugc thd tfch khdi chdp SAB'C'D' Bai Hudng ddn Six dung tfnh chat hinh chie'u khdng gian Cdng thiic tinh the tfch Xem hinh ve 92 Hoat ddng ciia HS Hoat ddng ciia GV Cdu hdi I Chung minh SM Imp(AEMF) Ggi y trd ldi cdu hdi I Ta cd tam giac SAC la tam giac ddu canh aV2 , dd AM SC Ta lai cd BD mp(SAC) nen BD ± SC ma BD // EF Vay SC EF Hay SC mp(AEMF) Cdu hdi Tfnh SB va SB' Cdu hdi TfnhEF Ggi y trd ldi cdu hdi Ta cd SO va AM la cac dudng trung tuye'n cia ASAC, dd ta cd : „^ a ^ EF SI —— = — = — hay EF = BD SO 3 Ggi y trd ldi cdu hdi Tuong tu ta cd : SB = V b ^ T ? SB' = 4J^\ Cdu hdi Tfnh SC va SC Ggi y trd ldi cdu hdi SC ± AC sc=V?4v7? SC' = Va2+b2+c2 Cdu hdi Ggi y trd ldi cdu hdi aVe Tfnh AM AM= Cdu hdi TinhV(sAEMF)' Ggi y trd ldi cdu hdi VAEMF)=^SM.AM.EF = ^ 93 Bai 10 Hudng ddn Six dung tfnh chat hinh chieu khdng gian Cdng thiic tfnh thd tfch B Xem hinh ve cau a Hoat ddng ciia HS Hoat ddng cua GV Ggi y trd ldi cdu hdi Cdu hdi I HS tu chiing minh Chiing minh ^(ABB'C) ^ ^ ( C A ' B ' C ) Ggi y trd ldi cdu hdi Cdu hdi ^(ABB'C) =^(C.A'B'C') ^ ^(ABCA'B'C) a'S 12 caub Hoat ddng cua HS Hoat ddng cua GV Cdu hdi Tinh thd tfch CAA'B'B 94 Ggi y trd ldi cdu hdi khdi chdp VAA'B'B) = V - V A ' B ' C ) = - V Ggi y trd ldi cdu hdi Cdu hdi T ' u ' -' ^(C.A'B'FE) inh tl so : —^^ ^(C.A'B'A) '^(C.A'B'FE) _ CE.CF V(c.ABA) CA.CB Ggi y trd ldi cdu hdi Cdu hdi Tfnh V(c.^,B.FE)theoV V -4 2^_8V ^(C.A'B'FE) - 27 ' Cdu hdi Gai y trd ldi cdu hdi Tinh V(c.A'B'FE) V _ a3V3 VA'B'FE)-27' Bai 11 Hudng ddn Six dung tfnh chat hinh chieu khdng gian Cdng thiic tfnh thd tfch D C Ggi O la tam hinh hop Hinh ve caua Hoat ddng cua HS Hoat ddng ciia GV Cdu hdi Ggi y trd ldi cdu hdi Chiing minh HS tu chiing minh Qua phep ddi xiing tam , hinh A'ECFA C.FA'EC bie'n Cdu hdi TInh ti sd hai thd tfch hinh Ggi y trd ldi cdu hdi Ti sd bing 95 Bai 12 Hudng ddn Six dung tfnh chat hinh chidu khdng gian Cdng thiic tfnh thd tfch B Hinh ve cau a Hoat ddng cua GV Cdu hdi I Hoat ddng ciia HS Ggi y trd ldi cdu hdi I Tfnh khoang each tit M ddn Khoang each dd la a mp(ADN) Cdu hdi Tfnh didn tfch tam giac ADN Cdu hdi Ggi y trd ldi cdu hdi sy Ggi y trd ldi cdu hdi Tuih V ( j ^ ^ p ^ ) V ^(M.ADN) ~ g caub Hoat ddng cua GV Cdu hdi Chiing minh ME // DN 96 Hoat ddng cua HS Ggi y trd ldi cdu hdi I Ta cd ME // DN mp(ABCD) // mp(A'B'C'D') Cdu hdi Chiing minh FN // ED Cdu hdi Chung minh A ' E = - ; B F = — Cdu hdi Tfnh V(F.DBN) Cdu hdi Ggi y trd ldi cdu hdi HS tu chiing minh Ggi y trd ldi cdu hdi Ta cd AFBN ~ ADD'E ; AA'ME-ACDN Tit dd ta cd A'E CN BN ED' TTT7 ~ T;;^' T:;7 = ^::— > ta cd dpcm A ' M CD BF DD' Ggi y trd ldi cdu hdi V ^(F.DBN) - J Ggi y trd ldi cdu hdi Tfnh V(D.ABFMA') a2 Ta cd S^pMg = — nen 'ABFMA' lla^ Dodd 12 lla^ V(D.ABFMA') ~ og Cdu hdi Tfnh V(D.A'ME) Cdu hdi Tfnh V(H) Cdu hdi Tfnh ti so hai thd tfch Ggi y trd ldi cdu hdi „2 Ta cd SAA'ME 16 Dodd Ggi y trd loi cdu hdi V - ^5a' V)-ii^ Ggi y trd ldi cdu hdi Tl sd hai the tfch la : — 89 97 HOAT DONG Tra ldi cau hoi trac nghiem chirdng I 10 B A A C B C C D B B HOATDQNG Gidi thieu mot so de kiem tra chifcfng t De sd PhAN Cau hdi va bai tap trac nghiem, mdi cau diem Hay chon cau tra ldi dung cac cau sau: Cdu I Cho hinh lap phuang ABCDA'B'CD' canh a Khi dd : (a) Thd tich khdi lap phuong la a ; (b) The tich khdi lap phuang la a ' ; (c) The tich khdi lap phuong la a^ (d) Ca ba cau tren ddu sai ,Cdu Cho hinh chop SABCD, day ABCD la hinh vudng canh a, SA= 3a va vudng gdc vdi day (a) Thd tich ciia hinh chdp la a^ (b) Thd tich ciia hinh chdp la — a^ (c) Thd tich ciia hinh chdp la — a^ (d) Ca ba cau tren ddu sai 98 Cdu Cho hinh chdp ddu ABCD canh a (a) Thd tfch ciia hinh chdp la (b) Thd tfch ciia hinh chdp la ,3 a-V2 a'^ a^V2 (c) Thd tfch cua hinh chdp la ; (d) Ca ba cau trdn ddu sai Cdu Cho hinh chdp tii giac ddu SABCD Day ABCD la hinh vudng tam O canh a SO = a va vudng gdc vdi day a^ (a) The tfch cua hinh chdp la — ; (b,™ chc.ah,„hch6p4; a^ (c) Thd tfch cua hinh chdp la — ; (d) Ca ba cau tren ddu sai PhAN Bai tap tu luan diem Cau (6 diem) Cho hinh chdp SABC SA AB, AB AC, AC ± SA Goij M, N lin lugt la trung diem SB va SC a) Tfnh ti sd hai thd tfch ciia hinh chdp mat phing AMN chia b) Cho SA = a, AB = 2a, AC = 3a Tfnh khoang each tit A de'n mat phing (SBC) De sd'2 PhAN Cau hdi va bai tap trac nghiem, mdi cau diem Cdu I Cho lang tru tam giac A B C A ' B ' C Mat phing (AB'C) chia lang tru hai jAiin cd ti sd thd tfch la 99 (a) ; (b) (c) ; (d) Hay chgn cau tra ldi diing Cdu Cho hinh lap phuang ABCDA'B'C'P' Mat phing (AB'D') chia hinh lap phuang tranh hai phan cd ti sd the tfch la (a) 3; (b) (c) ; (d) Hay chgn cau tra ldi dung Cdu Cho hinh chdp S.ABCD, day ABCD la hinh vudng eanh a Mat phing (SBD) chia binh chdp hai phan cd ti le la : (a) ; (b) (c) (d)4 Hay chgn cau tra ldi diing Cdu Cho hinh chdp SABCD day ABCD la hinh vudng canh a Ggi M la trung diem AB Mat phing (SMD) chia hinh chdp hai phan cd ti le la : (a) ; (b) (c) (d) Hay chgn cau tra ldi diing PhAN Bai tap tu luan diem Cau (6 diem) Cho hinh chdp SABCD, day ABCD la hinh vudng canh a, tam O SA = a, SA vudng goc vdi day a) Tinh the tfch hinh chdp ASBC b) Tinh khoang each tii A de'n mp(SBC) De sd'3 PhAN Cau hdi va bai tap trac nghiem, mdi cau diem Hdy dien ddng sai vdo cdc khdng dinh sau: Cdu Cho binh chop SABCD, day ABCD la hinh vudng tam O, SO = a va vudng gdc vdi day 100 (a) JTmh chdp S.OAB cd the tfch la — 12 D (b) Hinh chdp S.OAD ed the tfch la D 12 ,3 (c) Hinh chdp S.DAB cd thd tfch la D (d) ba khang dinh trdn ddu sai • Cdu Cho hinh bat dien ddu SABCDS' (a) Sd dinh ciia hinh bat dien la • (b) Sd canh cua hinh bat dien la D (c) Sd canh ciia hinh bat dien la 12 n (d) Sd eanh ciia hinh bat dien la 24 Cdu Cho hinh chdp S.ABCD (a) Ti sd thd tfch eua hai khdi chdp S.ABD va S.ABCD la V] (b) Tl sd thd tfch cua hai khdi chdp S.ACD va S.ABCD la Fl ^ (c) Ti sd thd tfch ciia hai khdi chdp S.CBD va S.ABCD la Fl ^ (d) Ca ba y tren ddu sai H Cdu Cho hinh lap phuang ABCDA'B'CD', day ABCD la hinh vudng canh a (a) Mat phang (CBD) chia khdi chdp phan ti Id la - [] (b) Mat phing (CBD) chia khdi chdp phan ti Id la \~\ (c) Mat phing (CBD) chia khdi chdp phan ti le la - [] 101 (d) Ca ba y tren ddu sai P PhAN Bai tap tu luan diem Cau (6 diem) Cho hinh chdp SABC, day ABCD la tam giac ddu canh a, G la trgng tam cua tam giac ABC, SG _L (ABC) a) Chung minh tam giac BSC la tam giac can b) Cho SA = a, tinh thd tfch khdi chdp H U O N G D A N - DAP AN De sd PhAN Cau hdi va bai tap trac nghiem, mdi cau diem Hdy chgn cdu trd ldi dung cdc cdu sau Cdu Cdu Cdu Cdu c a a b PhAN Bai tap tu luan diem (HS tu giai) De sd2 PhAN Cau hdi va bai tap trac nghiem, mdi cau diem Cdu Cdu Cdu Cdu b c a c PhAN Bai tap tu luan diem De sd PhAN Cau hdi va bai tap trac nghiem, mdi cau diem Cdu 102 a b e d D D D S Cdu a b c d D s D S a b c d D D D S a b c d D a' S S Cdu Cdu PhAN Bai tap tu luan diem Ban dgc tu giai 103 [...]... dinh, cgnh, mat cua (H') 2 Hai hinh bang nhau • GV ndu dinh nghla: Hai hinh dugc ggi Id bdng nhau neu nd cd mdt phep ddi hinh bie'n hinh ndy thdnh hinh kia GV su dung hinh 1 .12 de md ta dinh nghia tren • Thuc hien A 4 trong 4 phiit 12 B' A' Hoat dgng ciia GV Cdu hoi I Hoat dgng ciia HS Ggi y trd ldi cdu hoi I Ggi 0 la tam cua hinh hop Phep ABD.A'B'D' thanh hinh CDB.C'B'D' ddi xiing tam 0 bien hinh lang... 2 Cho hinh hdp ABCD.A'B'CD' Ggi O la tam ciia hinh hdp, phep ddi xiing tam D(o) 15 B' C ^.^^ A' y^ 1 "• D' \ -' B: **• • D (a)D(0)(A) = C' D (b)D(0)(B) = B' 1 D D (c)D(0)(B)-D' (d)D(0)(A) = C Trd ldi a b c d D S D S Cdu 3 Cho hinh hop ABCD.A'B'CD' Ggi O la tam ciia hinh hop, phep ddi xiing tam D, '(O) B' A' 1 y f j r N 1 ^ ^''' D' B yy y^' \ (a) D(0)(BAC.B'A'C') = DAC.D'A'C' D (b) D(0)(ABD.A'B'D')... nhidu van dd cd trong thuc te vd hai dudng thang vudng gdc Cd nhidu sang tao trong hinh hgc Hiing thii trong hgc tap, tich cue phat huy tfnh ddc lap trong hgc tap II CHUAN 51 CUA GV VA HS 1 C h u a n bi ciia G V : • Hinh ve 1. 17 den 1. 22 trong SGK • Thudc ke, pha'n mau, • Chuan bi san mgt vai hinh anh thuc te trong trudng vd hai dudng thang vudng gdc nhu: cac dudng thang cua tudng, 2 Chuan bj ciia HS... da giac ddu ciia Le-d -na Do Vin -ci a) b) Kiioi da dien 12 mdt 28 : ^ ^ a) b) Khd'i da dien deu 20 mat • Thuc hien ^ 2 trong 5 phiit Hay cho HS tu ve bat dien ddu Hoat dgng cua GV Hoat dgng cua HS Ggi y trd ldi cdu hoi I Cdu hoi 1 Hay de'm cac dinh cua bat dien Gdm 6 dinh ddu 29 Cdu hoi 2 Ggi y trd ldi cdu hoi 2 Hay dem cac canh ciia bat dien 12 canh ddu • GV cho HS didn vao bang tdm tat sau: Ten goi... Cho hinh chop ddu ABCD Gdc ADB bang D (a) 60°; (b) 12 0 °; (c) 90"; (d) 15 0° Trd ldi (a) Cdu 6 Cho tii dien deu ABCD Tdng ba gdc d dinh A la (a) 90° (b )18 0° (c) 45° (d) 30° Trdldi (b) Cdu 7 Cho mdt bat dien ddu Mdi gdc tai mdt dinh cua mdt mat la (a) 90° (b) 60° (c) 45° (d) 30° Trd ldi (b) HOAT DONG 6 mtftiQ DflN GIfll Bfll TAP SflCH GIflO KHOfl Bai 1 Day la bai tap thuc hanh GV yeu cau HS ga'p giay... Thuc hien vi du 1 trong 15 ' cau a Su dung hinh 1. 22 a trong SGK Hoat dgng cua GV Cdu hoi I Hoat dgng cua HS Ggi y trd ldi cdu hoi I Hay ve hinh va dat ten cho cac HS tu ve hinh va dat ten dinh cua bat dien Cdu hdi 2 Ke ten cac mat cua bat dien Ggi y trd ldi cdu hoi 2 HS tu liet ke toan bg Thuc hien ^ 3 trong 5 phiit 30 Hoat dgng ciia GV Cdu hoi I Hoat dgng cua HS Ggi y trd ldi cdu hoi 1 Hay chi ra mdt... mat phang (P) la phep ddi hinh c) Phep ddi xdng tdm O GV sit dung hinh 1. 1 la va ndu khai niem: Phep ddi xdng tdm O la phep biin hinh bie'n O thdnh chinh nd Bien mdi diem M khdc O thdnh M' md O la trung diem cua MM' H24 Hay chiing minh phep ddi xiing tam O la phep ddi hinh d) Phep ddi xiing qua dudng thdng A GV sii dung hinh 1. 1 la va neu khai niem: Phep dd'i xdng qua dudng thdng A la phep bien hinh... la cac tam giac ddu la tam giac ddu canh — cau b Sii dung hinh 1. 22 b trong SGK Hoat dgng cua GV Cdu hoi I Hoat dgng cua HS Gen y trd ldi cdu hoi 1 Hay ve hinh va dat ten cho cac HS tu ve hinh va dat ten dinh ciia bat dien Ggi y trd ldi cdu hoi 2 Cdu hoi 2 HS tu liet ke toan bd Ke ten cac mat ciia bat dien Thuc hien ^ 4 trong 5 phiit 31 A' Hoat dgng ciia HS Hoat dgng ciia GV Ggi y trd ldi cdu hoi I... S.DAB Trdldi (a) 19 Cdu 9 Cho hinh chdp deu S.ABCD (hinh ve) Qua phep ddi xung tam O bie'n hinh chop S.OAB thanh hinh chdp (a) S.DOA; (c) S.AOB ; s' (b) S.DOC (d) S.DOC Trd ldi (d) Cdu 10 Cho hinh chdp deu S.ABCD (hinh ve) Qua phep ddi xiing tam O bie'n hinh chdp S.ABCA thanh hinh chdp 20 (a) S.DOA ; (b) S'.ABCD (c) S.AOB; (d) S.DAB Trd ldi (b) HOATDQNG 7 HaOTNG DflN Bfll TflP SGK Bai 1 Hudng ddn Dua... 3 Hay neu mdt each chia khac Ggi y trd ldi cdu hoi 2 Van cdn nhidu each chia khac niia Ggi y trd ldi cdu hoi 3 HS tu neu 23 §2 Khoi da dien loi va khoi da dien deu (tiet 4, 5) I MUC TIEU 1 Kie'n thurc HS nam dugc: 1 Dinh nghia khdi da dien ldi, phan biet dugc khdi da dien loi va khdi da dien deu 2 Nam dugc dinh nghia khdi da dien ddu 3 Hieu rd tfnh chat ciia khdi da dien deu 4 Nhan bie't dugc mdt so ... ciia Kim tu B = 230.230= 11 3400 m' thap Cdu hdi Ggi y trd ldi cdu hdi Tfnh the tfch khdi chdp Kim tu V = - .11 3400 14 7 4 012 0 0m' thap • Thuc hien vf du 5' Sit dung hinh 1. 28 SGK cau a Hoat ddng... neu nd cd mdt phep ddi hinh bie'n hinh ndy thdnh hinh GV su dung hinh 1 .12 de md ta dinh nghia tren • Thuc hien A phiit 12 B' A' Hoat dgng ciia GV Cdu hoi I Hoat dgng ciia HS Ggi y trd ldi cdu... ve 1. 1 d^n 1. 14 • Thudc ke, pha'n mau, Chuan bj cua HS : Dgc bai trudc d nha, cd the lien he cac phep bien hinh da hgc d ldp dudi in PHAN PHOI THC5I LUONG Bdi dugc chia thdnh tie't: Tie't 1: