IV. TIEN TDM DAY HOC
a) Muc dich: Giiip HS cung ed kién thitc vd hinh thdnh ki ndng ve hiiu hai vectọ b) Hudng thuc Men:
b) Hudng thuc Men:
- Chifa cu the mgt sdbdi (17,18,19, 20) tgi ldp, tuy thugc thdi gian - Cdc bdi cdn lgi hudng đn ve nhd.
c) Qud trinh thuc Men.
Bai 14
Hudng đn
a) Vecto a ; b) VectoO ;
c) Vecto đ'i ciia vecto a + b la vecta-a - b . That vay, ta cd :
a + b + (-a-b) = a + b + (-a) + (-b) = 0.
B a i l s
Hudng đn
a) Tiir d + b = c suy ra d + b + (-b) = c+(-b), do đ d = c-b. Tuang tu
b = c-d.
b) Do vecto đi cua b + c la -b-c (theo bai 14c). c) Do vecto đ'i eua b-c la -b+c.
Bai 16. Hudng đn a) Sai: Do ^-'OB^'BA b) Diing ; c) Sai; do AB-AD = DB d)Sai; AB-AD = DB e) Diing. Bai 17 Hoat đng cua GV Cdu hdi 1
Tim tap hpp cac diem 0 sao cho
OA=OB;
Cdu hdi 2
Tim tap hpp cac diem 0 sao cho 'OÂ-OB.
Hoat đng ciia HS
Ggi y trd ldi cdu hdi 1
OÂ-'OB <^ O A - a e = 0 hay
fiA = 6 => 5 trung Ạ Trai gia thiet, do đ khdng cd diem 0 nao thoa man.
Ggi y trd ldi cdu hdi 2
0A + 0fi = 6 hay Ola trung diem A5.
Bai 18
Hoat đng cua GV
Cdu hdi 1
Hay tinh DA-DB
Cdu hdi 2
So sanh hai vecta BA va DC
Hoat đng ciia HS
Ggi y trd ldi edu hdi 1 DA-DB=BA
Ggi y trd ldi cdu hdi 2
Hai vecto nay đ'i nhau do 66
Bai 19
Hoat đng cua GV
Cdu hdi 1
Gpi I va r lan luat la trung diem cua AD va BC. Hay So sanh AI va ID ; C r v a r B
Cdu hdi 2
Tur AB = CD hay so sanh / / ' va
/ ' / . Tii đ rut ra ket luan.
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Hoat đng cua HS
Ggi y trd ldi edu hdi 1
Cac cap vecta nay bang nhaụ
Ggi y trd ldi edu hdi 2 AB = CD<^ Ai + ir + rB = cr + ri + iD o ir = n c^ i = r. Bai 20 Hoat đng ciia GV Cdu hdi 1
Gpi O la diem bat ki, hay phan tich mdi vecto thanh phdn thanh hieu hai vecto diem dau 0 .
Cdu hdi 2
Hay cdng cac vecta thanh phdn cua mdi ve tren va két luan
Hoat đng cua HS
Ggi y trd ldi edu hdi 1 AD=OD-OA,BE=0E-0B CF=OF-OC,AÊOE-OA,
BF^OF-OB,CD = OD-OC , AF^OF-OA,BD^OD-OB
CE=OE-OC.
Ggi y trd ldi edu hdi 2 AD+BE+CF^AE+BF+CD ^AJ+BD+^.