- Cho hpc sinh giai cdc de thi trong bd dk thi dai hpc
Cac bai toan ve phirong trinh bat phu-ong trinh
Phuong trinh, bat phuang trinh la phan kien thirc toan hgc ma hgc sinh
dupe hpc rdi rdc d nhieu Idp trong bdc hpc phd thdng. Vi the, khi dn tap d lap 12 chudn bi cho cdc ky thi, hpc sinh da quen di rat nhieu. Mot sd em da khdng cdn nhd den cdch gidi phuong trinh, bdt phuang trinh bdc hai, lugng gidc, mu
vd Idgarit. Trong khi dd, cdc dang todn ve phuong trinh, bat phuong trinh lai vd ciing phong phu, da dang ve kieu loai vd dp khd. De gidi dupe nd, hpc sinh phdi huy ddng din cdc kiln thiic, ky nang todn hpc khdng chi d bdc THPT md
thdm chi d ed bde tilu hpc, trung hpc co sd. Chinh vi the, trude khi bien soan npi dung cho day hpc day chuyen de ndy cdng trinh da tien hdnh dieu tra Id hdng kiln thiic cua hpc sinh bdng phuong phdp ddm thoai true tiep thdng qua
bdi day ddu tien:
" He thong hda cdc kiin thirc can nha vi phuang trinh, bat phuang trinh''
Sau khi ndm bdt dupe nang lire ban ddu cua ngudi hpc, cdng trinh xdy dung ke
hoaeh cho viec day hpc sinh cdch tu hpc,tir lap lo hdng kien thirc qua timg
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Dangl: Giai phuang trinh, bat phuang trinh vdi he sd bdng sd Dang 2: Giai va bien luan
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Dang 3: Tim dieu kien cua tham sd de phuang trinh, bdt phuang trinh thda man tinh chat nao dd.
Khi bien soan ndi dung de day cho hpc sinh cdch hpc cdc dang todn tren cdng trinh ludn ehu y tdi cdc vdn de sau ddy:
- Ndi dung bdi todn dua ra phdi ddp iing muc tieu Idp Id hdng kien thirc cua hpc sinh, khac sdu cdc phuang phdp gidi cua timg dang ddng thdi chira dung nhumg net dien hinh can nhd trong mdi dang todn khde nhau hoac tham chi ngay trong ciing mot dang.
- Thdi gian tren Idp vira dii de hudng ddn hpc sinh biet cdch tu hpc d nhd - Ludn chudn bi tdi lieu djnh hudng cho hpc sinh cdch tu hpc hoac bang cdc philu hpc tap; phdi cd kl hoach kiem tra viec tu hpc eiia hpe sinh. Danh thdi gian thich ddng dl hpc sinh dupe tu ren luyen,
Sau day Id minh hpa vl tdi lieu dinh hudng eho hpc sinh biet cdch tu hpe mot trong nhimg dang todn vl phuang trinh, bat phuong trinh vd gido vien cd thi kilm sodt dupe viec tu bpc cua hpc sinh,
Dan2h Giai phuang trinh va bat phuang trinh vdi he sd bdng sd Cdch ldm: Thudng sir dung mot sd phuang trinh sau day:
LBien doi tuang duang dua ve phuang trinh, bdt phuang trinh ca bdn dd co cdch gidi.
Cac vi du: Gido vien chira mau mdt sd vi du thi hien viec biin ddi tuong
duong dua vl cdc phuang trinh, bdt phuong trinh eo ban nhu la bae nhdt, hai,
vd ty, lupng gidc mu. Id ga cimg vdi nhimg phuong trinh cd net dae trung cdn
Mot so luu y khi bien doi tuong duong (khde sdu hgc sinh)
f t y / •> f
- Cae phep bien ddi ddng nhat (chuyen ve, phd ngoae, luy thira, khai cdn,.,)
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' Sli dung cac cdng thirc bien ddi lupng gidc, cdc hang dang thiic ...
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- Can chu y them mgt sd dang phuang trinh sau day
Dang 1: f(x) + g(x) = 1+ f(x).g(x) «(f(x)-l).(g(x) -1) = 0 o 'f(x) = 1
gix) = 1
Dang 2: af(x) + bg(x) = ab+ f(x).g(x) o (f(x)-b). (g(x)- a) =0<» fix) = b (adsbygoogle = window.adsbygoogle || []).push({});
g{x) = a
Dang 3: f^(x) =g\x); f^(x) =g\x); (Sir dung HDT dua vl pt tich)
Dang 4: f (x) + g2(x) = 0 « | ^ ^ ^
Giao nhiem vu cho hoc sinh i\x hoc o* nha
Gidi cdc phuong trinh sau bdng cdch bien doi tuang duffng
l : V 7 i 3 - V 2 x - l - V 3 A : - 2 2: x^ + V^m =1 3: V7x + l-V3x-18<V2x + 7 4:V: 2x^ +\>\-x 5: 4x2+ X. 2^^'+3.2' >^2 2' +8X + 12 6 : ( 4 x ' - l 6 x + 7).log3(x-3)>0 7:21og225(x-l)>log^ (V2X-1-1)- 5 8: 4cos2x + 3tg2x - 4V3 cosx + 2V3 tgx + 4 = 0 9: x^ - 2xsinxy + 1 = 0 10: 2cosx - Isinxl = 1 ll:Log,^3(3- Vr^2x + x^ ) = - n j2. sin3x-smx ^ ^ c o s ( 2 x - ^ ) Vl-cos2x