- Sd tinh, thlnh phd thu6c trung uong - Mat do ddn sd rron 1km2 noi rhanh He Noi. - Sd thdnh phd nu6c ta.
Ddng 5 :
- Ddn sd thi x6 it dAn nhat.
- Mat d0 dAn sd noi thhnh cao nhdt trong c6c
thinh phd
- DAn sd cira tinh dOng dAn nhAt
COt I : Di6n tich mOt trong 3 tinh hep nhdt
Cbt 2 :Mat do dan sd trOn 1km2 ctra TP thu6c
trung udng c6 mdt d6 cao nhAt. Cbt 3 : So d0 thi nudc ta.
Cbt 4 : Sd thinh ph6 thudc trung udng.
Cbr B : Nam ki ni€m
Cat 9: Tudi cira do thi cd thf hai sau HI NQi.
Cdt l0:Di0n tich tinh r6ng nhdt. COt l3:Chidu dei bd bidn nu6c ta.
Cdc con sd c6 thd duoc ldy lai dd lap sd kh6c.
Drip 6n sE dang trong THTT sd 339 (9.2005.) Chfc c6c ban giii duo. c nhidu s6 nhdt dd nhAn duo. c
qui ctra CLB. VT'T u loc bO 2 8 2 5 8 2 a 0 0 I 2 I J 8 2 6 5 0 0 0 2 7 9 9 5 3 9 + 5 0 0 9 I 0 A a 8 2 ,,} 0 5 6 6 1 + 4 0 0 0 0 3 1 t 0 1 3 0 0 0 0 a-1 5 0 0 0 0 0 31
Yq,p, ili 70fi71, 3Q0 d ?XArl Rt
hfdl/apt nfu G*td Earrfh ilaqn?it'&
xuf,r nAx rtt uot
Toa soan : 1878, orl nt,nri'lJ]i:frtJ,
DT-Fax:04.5144272
Email : toanhoctt@yahoo.com
a
TRONG SO NAY
Dinh cho Trung hoc Co sd - For Lower
Secondary Schools
Thai N^hdt PhuEng - Tim crlc tri cria
m6t bi6u thrlc mA c6c bidn c6 didu ki6n rdng bu6c.
Singapore Mathematical Olympiad
(sMo) 2oo5
Tim hidu siu thdm to6n hoc so cdp -
Advanced Elementary Mathematics
Tq. Duy Phxqng - Phuong trinh bAc ba
vd c6c hO th(tc hinh hoc trong tam gi5.c
Entrance Preparation
Nguydn Anh Dfing - EdnS Thanh Hdi -
V6'c6ch giii dd thi tuydn sinh dai hoc
m6n To6n kh6'i A ndm 2005
To6n hoc vh ddi sdng * Mathematics
and Life
Phan Thanh Quang - D6ng di6u chidc
16 roi.
Di6n dhn day hoc to6n - Math Teaching
Forum
Trd,n Phuong Dung - Lrrong gi6c trong To6n 9 vi trong chrlong trinh to6n phd
th6ng.
Nguy6n ThdThach - Tq, Duy Phxgng-
Thi khu vuc giAi to6n tr6n m6y tinh
CASIO ldn thrl nam - 2005.
O Chudn bi thi vio Dai hgc - University
@ Ciai bii ki trudc - Solutions to Previous
@ Phudng ph6p giii to6n - Math Problem
Solving
LA Qtlang Trung - Ung dgng cria m6t
bdt ding thrlc trong tam gi6c. Dd ra ki niy - Problems in This Issue
T1/337, ..., Tl2l337 , Ll, L21337 .
Problems.
GiiLi c6c bdi ctra sd ggg.
^-,
W Todn hoc mu6n miu - Multifarious
Mathematics
X h6i ? Y,Ztrhli:i..
Sai ldm & diu ? - Where's the Mistake? CAu lac bO - Math Club.
@
@
(D
DON DQC THTT Sei SSS (8.2oos). MQt sd bii todn vd tap hgp didm rh6a mdn m6t bat ding thrlc hinh hoc . MQt sd bii todn vd tap hgp didm rh6a mdn m6t bat ding thrlc hinh hoc . MOt sd phuong phdp xdc dinh gidi han c[ra ddy sd
r Vd mQt chung minh m6i cira bhi toiin bdn miu
. Kdt qui vi dd thi Olympic To6n Qudc td,2005.
r Phuong trinh bAc ba vd cdc h0 thrlc hinh hoc uong tam giSc (tidp theo)
o Kdt qui Cuoc thi Xudn ra dA - HA gidi ddp.
Mli c6c ban dat mua tap chi THTT tai Buu tli6n.
M0T s0 uuultc couo BANc Hiltn HoA
TRAN DINH VIEN (Hd N6i) Tap chi TH&TT sd 305 th6ng 11.2002 vd s6
332 thdng 2.2005 da gi6i thiOu vdi ban doc
dudng cong Hoa h6ng nhidu cdnh c6 phuong trinh (PT) tham sd ddi vdi h0 toa do Dd-C6c
vu6ng g6c Oxy trong mAt Phing :
lx =2a.sin(mt).cosI
{(l)
l.Y = 2a'sin( mt)'sint
trong d5 a li hang sd duong, m lit s6 tu nhi6n
Qn >- 2) cho tru6c, t li tham sd.
Dudng cong niy cd hinh dang mOt b6ng hoa
m clnh ddu nhau ndu m 16, hoac 2m cdnh ddtt
nhau ndu mchdn.
Tr) dudng cong Hoa hdng nhidu cdnh ta x€t m6t sd dudng cong tudng tu cfrng c6 dang hinh
hoa. Dd tiOn s6p xdp vh phAn loai chring, ta goi dudng c6 PT (1) n6i tr6n li dudng Hoa don l,ki
hieu li Ar. Dudi day xin gi6i thi6u v6i ban doc dudng cong Hoa don 2.
Dudng cong Hoa don 2
l. Phuong trinh.Trong mat ph&ng v6i h0 toa
d6 Dd-c6c vu6ng g6c Oxy, dudng cong c6 PT tham sd :
[x =a(l+sin(mt)).cosr
< 12)
l'Y =a(I+sin(mr)).sint
trong d6 a lI hang s6 duong, m ld sd tu nhiOn (m > 2) cho tru6c, r ld tham s6, goi li dudng
cong Hoa don 2, ki hiOu ldg2.
TiI m Q) cia dudng cong, ta suy ra :
. Chu ki cira dudng congA2ldT = 2r (kh6ng
phdn biOt m chdn hay 16).