THIẾT KẾ BÀI GIẢNG HÌNH HỌC 10 NÂNG CAO

TIEN TDINH DAY HOC Hay neu dinh nghia phuang trinh chfnh tic ciia dudng thing, mdi quan he cua nd vdi phuong trinh tham so.. • Xic dinh dugc tam va bin kinh ciia dudng trdn cd phuong tr

§3 Khoang each va goc (tiet 5, 6)

3 Thai do

• Lien he dugc vdi nhiiu van dl cd trong thyc t l lien quan din dudng phan giac

• Cd nhiiu sang tao bai toan mdi

• Cd tinh thin ham hge ban

II CHUAN BI CUA GV VA HS

1 Chuan bi cua GV:

1 GV: Chuin bi mdt sd cau hdi vl gdc giiia hai dudng thing, gdc giiia hai vecto

de hdi hge sinh

2 Chuin bi mdt sd hinh sin d nha vao giay hoac vao ban meca de chiiu niu cd may chiiu:

III PHAN PHOI THOI LUONG

Bdi ndy chia ldm 2 tiet:

Tiei 1: Td ddu den hit phdn HD 2

Tiet 2 : Phdn cdn lgi vd hudng ddn bdi tap

IV TIEN TDINH DAY HOC

Hay neu dinh nghia phuang trinh chfnh tic ciia dudng thing, mdi quan

he cua nd vdi phuong trinh tham so

B RM MOI

HOAT DONG 1

1 Khoang each tu mdt diem den mdt dudng thang

a) Muc dich Cho hge sinh ldm quen vdi mot cdng thifc tinh khodng cdch tif mgt

dem din mgt dudng thdng bang phuong phdp tog do

b) Hudng thitc Men

- Niu vd thifc hiin gidi bdi todn 1

- Niu vi tri tuong dd'i cua diem vd dudng thdng

-Thuc Men [?l]

- Neu va giii bai toin 2

-Thifc Men ^%2

- Niu vd hudng ddn HS thuc Men vi du trang 87 SGK

c) Qud trinh thuc Men

• Neu va thyc hien giai bai toan 1

- Neu bai loan va cho HS thao luan

GV ve hoac treo hinh 72 len bang

A^y

Hinh 72

Viec giai bai toan la khd ddi vdi hge sinh, vi vay GV cho bgc sinh xem xet ldi giai

va giai thfch nhiing van dl hge sinh cdn nghi vin hoac thic mic

Ddi vdi da so hge sinh, nen cdng nhan kit qui cua bai toan

k^M + by^ + cl d(M ; A)

v5 + b'

• Thyc hien lt\, 1

GV thifc hien thao tac nay trong 3'

Hoat ddng cua giao vien

Cau hdi 1

Hay tfnh khoang cich tii' diem M

din dudng thing A trong trudng

Cau hdi 2

Hay tinh khoang each tit diim M

din dudng thang A trong trudng

GV thifc hien thao tac nay trong 3'

Hoat dgng cua giao vien

Cau hdi 1

Cd nhan xet gi vl vi trf cua hai

diim M, N dd'i vdi A khi k va k'

Hoat ddng cua hge sinh Ggi y tra Idi cau hdi 1

k va k' ciing diu khi va chi khi M nim vl mdt niia mat phing bd A

vaN

Cau hdi 2

Cd nhan xet gi vl vi trf ciia hai

diim M, N dd'i vdi A khi k va k'

khic da'u ?

Ggi y tra Idi cau hdi 2

k va k' khac diu khi va chi khi M nim ve hai niia mat phing bd A

va N

• Neu kit luan

GV neu kit luan sau

Hai diim M, N nim ciing phia dd'i vdi A khi va chi khi

(axf^ + byf^ + c)(axp^ + by^ + c) > 0 ;

Hai diim M, N nim khic phia dd'i vdi A khi va chi khi

(ax;^ + byi^ + c)(ax^ + by^ + c) < 0

• Thyc hien - ^ 2

GV thifc hien tiiao tac nay trong 3'

Hoat ddng ciia giao vien

Ggi y tra Idi cau hdi 2

A va B cung phfa dd'i vdi A =J> A khdng cit canh AB;

A va C; B va C khac phfa dd'i vdi A=> A cit cac canh AC va BC

• Neu va giai bai toan 2

- GV neu bai toan va cho HS thao luan bai tdin

- GV Ve hmh 73 len bang

Hinh 73

Cho HS tra ldi cac cau hdi sau

HI Cho hai dudng thing cit nhau Hay tim tap hgfp cac diem each diu hai dudng

thing 66

• Thyc hien " ^ 3

GV thifc hien thao tac nay trong 3'

Hoat ddng cua giao vien

ciia gdc tao bdi Aj va A2 K h i d i = d 2

\aix + biy + ci\ «2^ + ^2>'+ ^2

Diy la bai toan van dyng hai kT nang:

- Vi tri cua hai diim dd'i vdi mdt dudng thing

- Phuang trinh dudng phan giic ciia hai dudng thang

GV cin dua ra cac cau hdi:

HLHay viit phuang trinh hai dudng phan giac trong va ngoai cua gdc A

H2: A la phan giac trong cua gdc A khi nao?

Sau dd hudng din hge sinh giai bai toan

Ket qud

Dudng phan giac trong la mdt trong hai dudng

4x + 2y -13 = 0 (dudng phan giic d^)

4x - 8y + 17 = 0 (dudng phan giac Thu toa do B va C vao phuang trinh cua dj va d2 va su dyng tinh chit

^2)-* B va C nim ciing phfa vdi dudng thing thi dudng thing do la phan giac ngoai

* B va C nim khic phia vdi dudng thing thi dudng thing dd la phan giac trong

i/2: 4 x - 8 y + 1 7 = 0

HOAT DONG 2

2 Gdc giiia hai dudng thing

a) Muc dich Cho hge sinh ldm quen vdi mgt cong thifc ve goc giica hai dudng

thdng

b) Hudng thuc Men

- Niu vd dinh nghia ve goc giila hai dudng thdng

- Neu vd hudng ddn HS thuc hiin vi dii trang 87 SGK

c) Qud trinh thitc Men

• Neu dinh nghia

Dinh nghTa

Hai dudng thing a va b cit nhau tao thanh bd'n gdc So do nhd nhit cua

cic gdc 66 dugc ggi la so do ciia gdc giira hai dudng thing a va b, hay

don gian la gdc giila a va b

Khi a song song hodc triing vdi b, ta quy udc gdc giifa ehiing bdng 0

• Thyc hien [?l|

GV ve hinh 74 va cho HS thao luan cau hoi

GV thifc hien thao tac nay trong 2'

Hoat ddng cua giao vien

Cau hdi 1

Gdc giii^ a va b bing bao nhieu

do?

Cau hdi 2

So sanh gdc dd vdi gdc giua hai

vecto M , V va gdc giiia hai vecto

Gdc giiia hai dudng thing cit nhau a va b, kf hieu la (a, b), ludn nhd

hon hoac bing 90 nen ta cd

(a,b) = (u ,v) niu (u , v ) < 90 , (a, ^) = 180° - (/7, V ) niu (/7, v ) > 90°, trong dd u, v lin lugt la vecto chi phuong cua avab

• Thyc h i e n ^ r 4

GV thifc hien thao tac nay trong 3'

Hoat ddng cua giao vien

Cau hdi 1

Tim toa do vecto chi phuang cua

hai dudng thing

• Neu va giai bai toan 3

GV neu bai toan 3, cho HS thao luan cau hdi Giai bai nay bing

• Thyc hien ^ r 5

GV thifc hien thao tac nay trong 3'

Hoat ddng ciia giao vien

Cau hdi 1

Tim cosin ciia gdc giiia hai

dudng thing A, va Ai Iin lugt cho

bdi cac phuang trinh

ajX + bjy + Cl = 0 va

a2X + b2y + C2 = 0

Cau hdi 2

Tim diiu kien de hai dudng thing

Al va A2 vudng gdc vdi nhau

Hoat ddng ciia hge sinh Ggi y tra Idi cau hdi 1

cos(^l, ^2) trong dd hi, «2

Iin lugt la vecto phap tuyin cua Ay, A2

b) A] J_ A2 <=> a\a2 + b\b2 = 0

• Thyc hien^C 6

GV thifc hien thao tac nay trong 3'

Hoat ddng ciia giao vien

Cau hdi 1

Hoat ddng ciia hoc sinh Ggi y tra Idi cau hdi 1

va A2 trong mdi trudng hgp sau

Tim gdc giiia hai dudng thing zl,

va ZI2 trong mdi trudng hgp sau

b) zl, : x = 5 ;

Zl2:2x + y - 14 = 0 ;

Cau hdi 3

Tim gdc giira hai dudng thing Zl,

va ZI2 trong mdi trudng hgp sau

TOM TfiT Bfil HOC

l.d(M;A) = \ax^ + by^ + e\

\fa' + b'

1 ' Hai diim M, N nim cimg phfa dd'i vdi Zl khi va chi khi

(axf^ + byj^ + c)(ax^ + byj^i + c) > 0 ;

• Hai diim M, V nim khic phfa dd'i vdi zl khi va chi khi

(axj^ + byj^ + c)(axp^ + byj^ + c) < 0

3 Phuo'ng trinh hai dudng phan giac ciia cac gdc tao bdi hai dudng thing dd co dang

^ i x + biy + ci ^ a2X + b2y + C2 ^

cos(/7i,«2) trong do «}, «2 lin luot

la vecto phip tuyen ciia Zl,, ZI2

b) A, 1 A 2 <=> flifl2 +^1^2 = 0

HOAT DONG 3

HCrCFNG DfiN B^l T6P SGK

a) Muc dich Qua cdc bdi tap HS dn tap lgi kii'n thifc vd ren luyen ki ndng

b) Hudng thifc Men

c) Qud trinh thuc Men

mi(AB, A C ) < 9 0 ° n e n ( A B , AC) = (AB, A C ) « 4 3 ° 3 6 \

Bai 17

Hudng din

-Tim M diim each A mdt khoang h

-Viit phuang trinh qua M song song vdi A Cd hai dudng thing nhu vay niu h >

Bai 18

Hudng din

Ggi vecto phap tuyen ciia dudng thing la n = (a;b) Viit phuang trinh dudng thing di qua P cd vecto phap tuyen n

Su dyng cdng thiic tinh khoang each, ta tim dugc a, b

Cd hai phuang trinh A la x + 2y -14 = 0 va y - 2 = 0

Bai 19

Hudng dan

Ggi dudng thing la A va nd cit hai triic tai A(0 ; a), B(0 ; b) Theo gia thilt ta dugc MA = MB Ap dyng cdng thiic khoing each hai diem, ta dugc kit qua Dap sd Khdng cd dudng thing nao

Bai 20

Hudng dan

Viet phuang trinh hai dud'ng phin giac cua cac gdc tao bdi hai dudng thang tren Viet phuang trinh cac dudng thing di qua P va vudng gdc vdi hai dudng thing tren, dd la cac dudng thing cin tim

A:(l + A/2)(x-3) + ( y - I ) = 0 va A': ( I - V 2 ) ( x - 3 ) + ( y - l ) = 0

~ .«»

MOT SO Bfil Tgp TRfiC NGHIEM

Caul Khoang cich tii diim M( 1; -1 ) tdi dudng thing 3x- 4y -17 = 0 la:

'^> I o

Cau.8 Cho dudng thing di qua hai diem A(3 ; -1) va B(0 ; 3), tim toa do diem M

nim tren Ox sao cho khoang each tii M tdi dudng thing AB bing 1

(a) (1;0)- (b) (3,5; 0)

Cau 10 Cho hai diim A( 1; - 2) vi B( - 1 ; 2) Dudng thing nao sau day la trung trye

cua doan thing AB ?

(a) X - 2y + 1 = 0 (b) 2x + y = 0 (c) x - 2 y = 0 (d) x + 2y = 0

Trd ldi Chgn (c)

Ciu 11 Cho hai diim A( 2; 3) va B(l; 4) Dudng thing nao sau day each diu hai

diem A va B ?

(a) x-y + 100 = 0 (b) x + y -2= 0 (c) x+ 2y = 0 (d) 2x-y +10 = 0

§ 4 Du'dng tron (tiet 7, 8, 9)

I MUC TIEU

1 Kien thiifc

HS nim dugc:

• Vie't dugc phuang trinh dudng trdn trong mdt sd trudng hgp don gian

• Xic dinh dugc tam va bin kinh ciia dudng trdn cd phuong trinh dang (1), Biit dugc khi nao (2) la phuang trinh dudng trdn va chi ra dugc tim va ban kfnh cua dudng trdn dd

• Vie't dugc phuang trinh tilp tuyin ciia dudng trdn khi bie't toa do ciia tilp diem hoac bie't mdt yiu td xic dinh tilp tuyin dd

2 KT nang

• Viet dugc phuang trinh dudng trdn: Di qua ba diim, biet tim va ban kinh

• Xic dinh dugc mdt dudng thing la tilp tuyin ciia dudng trdn

3 Thai do

• Lien he dugc vdi nhiiu van dl cd trong thyc t l lien quan din dudng trdn

• Sang tao bii toin mdi

• Phit huy tinh tich eye trong hge tap

• Cd dc tudng tugng td't ban

n CHUAN Dl CUA GV VA M

1 Chuan bi cua GV:

11 GV: Chuin bi mdt sd cau hdi vl dudng trdn da hge d ldp 9

2 Chuin bi mdt sd hinh sin d nha vao giiy hoac vao ban meca de chiiu niu cd may chiiu: hinh 75

Ngoii ra cdn phai ve sin mdt so' hinh 6e hudng din hge sinh thyc hien cac HD

Chuin bi phin mau

2 Chuan bi ciia HS :

HS : Chuin bi td't mdt sd cdng cy dl ve hinh: Thudc ke, compa,

III PHAN PHOI THOI LUONG

Bdi ndy chia Idm 3 tiii:

TieiL'Mucl vd2

Tiet 2 : Muc 3;

Tiei 3: Hudng ddn bdi tap

IV TIEN TDINH DAY HOC

1 Phuang trinh dudng trdn

a) Muc dich Cho hge sinh ldm quen vdi mgt cdng thitc ve gdc giifa hai dudng

thdng

b) Hudng thuc Men

- Niu vd dinh nghia phuong trinh dudng trdn

-Thue hiir^\^ 1

c) Qud trinh thitc Men

• Niu vd dinh nghia phuong trinh dudng trdn

-GV ve hoac treo hinh 75 len bang

Hinh 75

- GV cho HS tra ldi cac cau hdi sau

HI Dinh nghia dudng trdn

H2 Hay tinh khoang cich MI

H3 Vie't phuong trinh dudng trdn

Phuong trinh cua dudng trdn (^)

Hay xic dinh bin kfnh cua dudng

Hoat ddng ciia hge sinh Ggi y tra Idi cau hdi 1

R = PQ = Vl6 + 36 = V52

HOAT DONG 2

2 Nhan dang phuong trinh dudng trdn

a) Muc dich Cho hge sinh ldm quen vdi cdc dgng phuong trinh difdng trdn b) Huong thitc Men

-Xdc ddih tdm vd bdn kinh ciia dudng trdn

-Thuc Mii^\^ 2

-Thitc Men [Y]

Hudng ddn HS ldm vi du trang 92

c) Qud trinh thifc hien

• Xac dinh tam va ban kinh ciia dudng trdn

- Xac dinh dang ciia phuang trinh dudng trdn

x2 + y2 - 2xoX - lyQy + x^ + y^ - /?^ = 0

- Ta bie'n ddi phuang trinh (2) vl dang

- Ne'u ggi / la diim cd toa 6g {-a ; - b), cdn (x : y) la toa do ciia diem M thi ve trii cua ding thiic tren chfnh la IM^

Phuang trinh x~ + y^ + 2ax + 2by + c = 0, vdi diiu kien a^ + b^ > c, la phuang trinh ciia dudng trdn tam I(- a ; - b), ban kfnh R

Khi a' + b = c hay tim tap hgp

cac diem M cd toa do (x : y) thoa

man phuang trinh (2)

Cau hoi 2

7 2

Khi a' + b < c, hay tim tap hgp

cac diim M cd toa do (x ; y) thoa

man phuang trinh (2)

Ggi y tra Idi cau hdi 1

GV thu'c hien thao tac nay trong 3'

Gl' chia ldp thdnh 4 nhom (co the lay theo to) sau do cho cdc td iin diin kei qud

Cdch 2 Viet phuong trinh dudng trung trye cic doan thing MN, NP rdi tim giao

diim ciia hai dudng nay chfnh la tam cua hai dudng trdn Tit dd tim dugc ban kfnh

GV nen dat cac cau hdi dl hge sinh tra ldi, giai quylt vin dl, tii dd giai quylt ldi giai cua bai toan

Kit qua

Phuong trinh dudng trdn la

( x - 3 ) ^ + (y + 0,5)'^=10,25

HOAT DONG 3

3 Phuang trinh tiep tuyen ciia dudng trdn

a) Muc dich Cho hge sinh ldm quen vdi cdc dgng phuong trinh tii'p tuyin ciia

dudng trdn

b) Hudng thitc Men

- Niu vd hudng ddn HS ldm bdi todn 1

- Niu vd hudng ddn HS ldm bdi todn 2

-Thitc hien'^\^ 3

- Thuc Men ^ C 4

c) Qud trinh thifc Men

• Neu va hudng din HS lam bai toan 1

Dau tien GV dat cac cau hdi de hge sinh giai quyet vin dl lien quan din ldi giai bai toan

HI M cd thudc (^) hay khdng?

H2 Tim tam I cua dudng trdn

H3 Tiep tuyen Mt cd quan he gi vdi IM?

Ne'u b = 0,ta cd the chgn a = iva dugc tilp tuyen

4 : X - V5 + 1 = 0

NIu lb + v 5 a = 0, ta cd the chgn a = 2 va /? = - v 5 va dugc tilp

tuyin

zl2 : 2 x - V5y + 2 - Vs = 0

- GV neu diiu kien de dudng thing la tilp tuyen

Difdng thdng tii'p xuc vdi dudng trdn khi vd chi khi khodng each td tdm dudng trdn de'n dudng thdng bdng bdn kinh ciia difdng trdn Tuy nhien, dl viit phuang trinh tiep tuyin ciia dudng trdn tai diim M

cho trudc thudc dudng trdn, ta cd each giai don gian ban

• Neu vi hudng din HS lam bai toan 2

- GV neu bai toin cho HS thao luan

- GV ve hoac treo hinh 76 len bang

y k

Hinh76

Sau dd cho HS tra ldi cac cau hdi

HI Khi nao M nim tren dud'ng trdn?

H2 Hay chiing to M nim tren dudng trda

Hay viit phuang trinh tilp tuyen ciia dudng trdn

Phuang trinh tiep tuyin ciia dudng trdn I

3x + 4y - 20 = 0

• Thyc hien ^ f 3

GV thirc hien thao tac nay trong 3'

Hoat ddng ciia giao vien

Viet phuang trinh dudng thing di

qua gdc toa do va tilp xiic vdi

Hoat ddng ciia giao vien

Cau hdi 1

Tim vecto phip tuyin cua

tie'p tuyin nay

Cau hdi 2

Hay vie't dang ciia tilp

tuyin

Cau hdi 3

Tinh khoang cich tit tam

dudng trdn den tiep tuyin

Tit dd vit phuang trinh ciia

la 3x - y - 9 + VlO = 0

va 3x - y - 9 - VlO = 0

TOM TfiT Bfil HOC

1 Phuong trinh dudng trdn tam 1 (x„; y,,) bin kinh R cd dang

.(x-xo)^ + ( y - y o ) ' = ^ '

•Phuang trinh x + y + 2ax + 2by + c = 0, vdi diiu kien

a^ + b^ > c, la phuang trinh ciia dudng trdn tam 1(- a ; - b), ban kinh R bing

^' + b'- -c

2 Dudng thing tilp xiic vdi dudng trdn khi va chi khi khoang each tir tim dudng

trdn de'n dudng thing bing ban kinh ciia dudng trdn

HOAT DONG 3

MCTONG D ^ N Bfil T6P SflCH Gi60 KHOfi

a) Mtic dich Giiip HS

-Thdng qua bdi tap on tap lgi kii'n thifc ve dudng trdn

- Ren luyen ki ndng gidi todn

b) Hudng thitc Men

-Gidi tgi ldp mot sdbdi tap tren ldp

-Mot sdbdi tap hudng ddn ve nhd

c) Qud trinh thitc Men

Bai 21

Hudng dan

a)Dungdo A2 + B2 - C = ^ + ^^^^^^—0>0

4 4 Cau b) va d) diing

Goi y tra Idi cau hdi 2

Phuo'ng trinh dudng trdn la : ( x - l ) ^ + (y-3)2 = 8

Bai toin nay cd thi giai bing 2 cich

Cich 1 Ggi phuong trinh dudng trdn la (x- a) + (y - b) = R^ Thay toa do cic diim vao phuong trinh dudng trdn, ta dugc ba he phuong trinh, giai ra

ta dugc a, b, R

Cich 2 Viet phuang trinh cic dudng trung trye ciia AB va BC Giao cua hai dudng trung trye dd la tam cua dudng trdn

DS : (X - 3)2 + y^ = 8

Bai 25

Hoat ddng ciia giao vien

Cau hdi 1

Hay neu phuong trinh tdng quit

ciia dudng trdn tam l(a ; b) ban

Ggi y tra Idi cau hdi 2

Vi dudng trdn tie'p xiic vdi Ox va Oy nen

1 b 1 = 1 a 1 = R hay a = b = R

Ggi y tra ldi cau hdi 3 Kit hgp vdi diiu kien dudng trdn di qua diem (2 ; 1) ta cd phuo'ng trinh :

(2 - a)2 + (1 - a)^ = a^ c^ a = 1 ; a = 5 Vdi a = I ta cd phuang trinh dudng tron

HS cd thi lam bai toan bing nhiiu each

Thay x, y tit phuang trinh dudng thing vao phuang trinh dudng trdn ta dugc mgt phuong trinh theo t Tir dd ta tim t, va quay Iai tim x, y

A(1;-2),B( 21 )•

Hay neu dang tilp tuyin ciia

dudng trdn song song vdi dudng

Ggi y tra Idi cau hdi 2

diiu kien tilp xdc, ta cd

Hay neu dang tiep tuyin ciia

dudng trdn song song vdi dudng

Cdu c)

Hoat ddng cua giao vien

Cau hdi 1

Hay neu dang tilp tuyen ciia

dudng trdn song song vdi dudng

thing da cho

•

Cau hdi 2

Hay vie't phuong trinh tiep tuyin

Hoat ddng cua hge sinh Ggi y tra Idi cau hdi 1

Tie'p tuyin ein tim cd phuang trinh : A(x

- 2) + B(y + 2) = 0 (A2 + B2 9^ 0) Tit diiu kien tilp xiic ta co

NIu B = 0 thi A ^ 0, ta dugc tilp tuyin x

- 2 = 0

Bai 28

Hudng din

HS giai theo cic budc sau

- Tim tam va bin kinh ciia dudng trdn

- Tim khoang each tii tim dudng trdn din dudng thing ching ban la k

NIu k < R, dudng thing cit dudng trdn, neu k = R dudng thang tilp xiic vdi dudng trdn, ne'u k > R dudng thing khdng cit dudng trdn

Trd ldi Chgn (c)

Cau 2 Phuang trinh nao dudi day khdng phai la phuang trinh ciia dudng trdn ?

Cau 4 Dudng trdn nao dudi day di qua diem A (4;-2) ?

(a) x2 + y2 -6x -2y + 9 = 0 (b) x^ +y2-2x - 6y -15 = 0

Cau 7 Cho ba diem (1; 0 ) , (0; I) va (0; 0)

Dudng trong nao dudi day di qua ba diem tren

(a) x2 + y2 + 2x + 2y -2= 0 (b) x^ + y^ -2x - 2y + 2 = 0

(c) x^ + y2 + - V 2 x - V 2 y = 0 (d) x ^ + y 2 - 2 x - 2 y - 2 = 0

Cau 8 Cho dudng trdn x2 + y^ + 2x'+ 2y - 9 = 0 Khoang each tii tam dudng trdn dd

tdi trye Ox bing bao nhieu ?

(a) V2 (b) 9

(c) -1 (d) 1

Trd ldi Chgn (d)

7 2 Cau 9 Tam dudng trdn x + y - 4 x + I = 0 each trye Oy mdt khoang bao nhieu ?

Caul2 Dudng trdn x + y -4x -2y +1= 0 tiep xdc vdi dudng thang nao trong cic

dudng thing dudi day?

(a) Trye tung (b) Trye hoanh

(c) 4x+ 2y - 1 = 0 (d) 2x+y - 4 = 0

Trd ldi Chgn (a)

Caul3 Dudng trdn x +y -6x = 0 khdng tie'p xdc vdi dudng thing nao trong cac

dudng thang dudi day?

(a) Trye tung (b) x-6 = 0

Caul5 Mdt dudng trdn cd tam I( 1 ;3 ) tie'p xiic vdi dudng thang 3x + 4y = 0

Hdi ban kfnh dudng trdn bing bao nhieu ?

* ' " ( b , ^ •

(c) 15 (d) 1

Trd ldi Chgn (a)

§5 Difdng: elip (tiet 10, 11, 12)

1 MUC TIEU

1 Kien thurc

HS nim dugc:

• Hieu va nim viing dinh nghia elip, phuong trinh chinh tic cua elip

• Tut mdi phuang trinh chinh tic cua elip, xic dinh dugc cac tieu diem, true ldn, trye be, tim sai cua elip va ngugc lai, lip dugc phuang trinh chfnh tic ciia elip khi bie't cic yiu td xac dinh nd

2 KI nang

• Vie't dugc phuang trinh elip khi biit 2 trong 3 yiu td a, b, c

• Xic dinh dugc cic yeu to ciia elip khi bie't phuong trinh elip

3 Thai do

• Lien he dugc vdi nhiiu vin dl cd trong thyc t l lien quan din hinh elip

• Cd nhiiu sang tao bai toan mdi

• Phit huy tfnh tich eye trong hge tip

• Cd dc tudng tugng td't ban

II CHUAN BI CUA GV VA HS

1 Chuan bi cua GV:

1 GV: Chuin bi mdt sd dyng cy de ve elip

2 Chuan bi mgt sd hinh sin d nha vao giay hoac vao ban meca dl chiiu neu cd miy chie'u:hinh 80, 81, 82, 83, 84 va hinh 85

Ngoai ra cdn phai ve sin mdt so hinh de hudng din bgc sinh thyc hien cac HD Chuan bi phin mau

2 Chuan bi cua HS :

- HS chuin bi td't mdt so cdng cy de ve hinh: Thudc ke, compa,

- Dgc trudc bai d nha

III PHAN PHOI TH6I LUONG

Bdi ndy chia ldm 3 tiii:

Tiet 1: Muc 1 vd 2

Tiet 2 : Muc 3;

Tiet 3: Hudng ddn bdi tap

IV TIEN TPINH DAY HOC

1 Dinh nghTa dudng elip

a) Muc dich Giiip HS

Hieu khdi niim dudng elip

Dinh nghia difdng elip

b) Hudng thuc Men

- Thue hiiiWt 1

c) Qud trinh thitc Men

• Thyc hien ^ f 1

- GV treo hinh 80 len bang

- GV nen dl hge sinh thyc hanh va GV dat cau hdi

HI Hinh viia ve cd phai hinh trdn hay khdng?

Hinh 80

• Thuc hien ?1

GV thiTc hien thao tac nay trong 3'

Hoat ddng ciia giao vien

Chu vi tam giac khdng ddi

Ggi y tra Idi cau hdi 2

Khdng ddi

• GV neu dinh nghia

Cho hai diem c6dinh Fj va F2, vdi F^F2 = 2c (c > 0)

Dudng elip (cdn ggi la elip) Id tap hgp cdc diem M sao cho MFl + ^f^2 - 2^, trong do a Id so cho trudc ldn hon c

Hai diem Fj vd F2 ggi la cdc diu diem ciia elip Khodng cdch le duoc ggi Id tiiu cU ciia elip

HOAT DONG 2

2 Phuong trinh chinh tic cua elip

a) Muc dich Giiip HS hieu duoc dinh nghia vd viei duoc phuong trinh chinh tdc

eiia elip

b) Hudng thuc Men

-Thue Men

-Thuc Men i^_ 2

-Vieiphuong trinh chinh tac cua elip

- Cho HS ldm vi du 1

- Cho HS ldm vi du 2

c) Qud trinh thitc Men

- GV neu vin dl thilt lap he trye toa do gin vdi elip

GV thi/c hien thao tac nay trong 2'

Hoat ddng ciia giao vien

Cau hdi 1

Vdi each chgn he trye toa do nhu

vay, hay cho biit F1F2 quan he

Hoat ddng cua hge sinh Ggi y tra Idi cau hdi 1

Fl va F2 thudc Ox, va F1F2-L Oy