2.Tinh chdt vd hinh dang cila dudng congA2 Tru6c hdt tn (2) tathdy x,l ddng thdi trict ticu
khi vi chi khi 1 + sin(zrr) = 0 o mt -
-!+2kn, (k e Z).
2
Suy ra, duong cong A2 di qua gdc toa dd O
fng vdi cdc grd tri tham sd
Tc ?Tt--:" +::k,(keD (3) t--:" +::k,(keD (3) 2mm v D2 43 ., Hinh 2a
GqiGliL vbng trbn luong gi6c tdm O, brin kinh
2a,v6i didm ddu ld A (2a; 0). TrOn G taldy cdc
didm A; (i = 1, 2, ..., m) (xem hinh 1) sao cho
rc 2xAA: '2mm=--+-i AA: '2mm=--+-i
Ki hi6u D; lh trung didm cira c6c cung AiqAi (i = 1, 2, ..., m ; coi Ao trirng vdi A.) ta c6
6, = - J-*L (2i - L), (i = 1,2, ..., m) (5)
'2mm
TU d6 suy ra m6t s6 tinh chdt ciaA2:
a)Trong m\t chu ki [0,2n), dudng congArdi
qua didm goc m ldn r?ng vdi cdc gid tri tham sd:
Tc 2n.
t;= - -L + -'- i (l = 1, 2, ..., m) (6)
'2mm
ddng thdi fiAp xfic vdi bdn klnh OA; crta vbng trdn V tai O.
(){em fiAlp tang 30)
A1N N
Hinh 2b
Curtc thi rui
frttifr MDi, jti #Ut frAy
CuOc thi dd di duoc hon nfta chdng dudng.
Nhidu ban g*i bdi vd ldm dilng duoc h€i cdc ciu
hdi. Bdi duoc gitii lA bdi khdng nhfrng dilng md
cdn phdi hay, ngdn gon, sdng sfia. Sd ndy cluing
t6i ddng ddp dnvd 3 cdu hdi dot I vd danh sdch mdt s6'ban c6 ldi gidi ni. Cdc ban chd doc k€'t
qud cudi cing ctia cu6c thi ddng tr€n THTT s6'
328 (8.2005). Chtic cdc ban may mdn. Du6i dAy ld d6p r{n 3 bdi cira dot 1.
nAl f . Cdch t. DDng 2 cong thrlc :
s= X_ r . ltll _[Ltl *[r:]l*.
L 4 ) Lr00_l 1400_l
r=s- zEl.r17) 17)
trong d5 : X lh ndm, C li s6 thrl tu cira ngdy cdn
tinh trong nam d6, f le thf.
NAm 1964 nhu6n n6n :
s = re63 . [uql-[r2ql.[r2€f +28e=2727
l4 ) Lr00_l 14001
r=2727-7.W21+l=5.
L7.l
VAy ngiy 15.10.1964 lh thrl nam.
Cdch 2. (Theo L€ Quang Huy, lO Todn,
chuyOn Lc Quf Ddn, TP V[ng Tiu).
Tir nam 1965 ddn ndm2004 c6 40 nam gdm
10 nam nhu0n vI 30 nam khong nhuAn.
_Coi ngiy 15.10.1964 ld sd I rhi ngey
15.4.2005Ii sd :
l7 + 30 + 31 + 365.30 + 366.10 + 31 + 28 +
31+15=14793
md, 14793 chia 7 du 2 n6n ngiy 15.10.1964 le thri nam (lii 1 so v6i thf 6 ngly-l5.4.2005).
BAI 2. M6i qudn chuydn vdo 6 rrdng kd ben
theo 4 hudng duoc ki hieu nhu sau : rrdi (T),
phii (P), len tr6n (L), xuong dudi (X). Dudi ddy
th cdch chuydn qudn til hinh I sang hinh 2 th6-a
m6n tdng cdc sd theo hdng ngang, theo cot doc
ddu bang 30 : 14X, l5X, 10P, 6P, 7L,8L, tzT, ttx, 15T, 14L, 1lP, 15X, 8P, 3P, 4L, LzT, 15T, 8X, 3P,4P, IzL,15T,4X,7X, 5X, gT,6L, 10T, 13X,6P, 10L, 5P, 9X, 10T, 6T, 13L, l4L,3P, gL, 11T. ISSN:0866-8035 Chisii : 12884 Misii:8BT39M5
Chf i rang vdi m5i ma phuong khi ddi ch6 2
hing c{ro nhau (gifr nguyOn rhf tu trong hdng)
hoac deii ch5 2 c6t cho nhau (gi[ nguyOn thri iu
trong cQt) thi lai duoc m6t ma"phuo"rg, ao aO
"5 th6 chon ma phuong sao cho hai quAn ghi cDng
mQt sd cira ma phuong d6 vh hinh I kh6 gzin
nhau thi theo vi6c chuydn quAn dd phfc tap.
Ldi giii tr€n lh c[ra ban Ngu1,€rt Dinh Lai,
11A3, THPT ThuAn Thinh 1, Bdc Ninh, ngudi lap ki luc vd s6 budc chuydn tluan it nhat (40
bu6c), it hon s6 bu6c chuyrin quan cria tdc gih bhi niy (42 bl6c, gift nguyOn vi tri citc sd \,2, 5,6 6 hinh 1), tiep theo ld c6ch chuytln cria ban
Vfr Thi H6ng Hanh, 6A, THCS B6C Lenh, Lio
Cai (46 budc), Dodn H6ng Qudn, tl\2, THPT
S5c Son, Hn NOi (48 budc), Dd Xudn Bac,P22,
K48 hgc viOn Phbng khOng Kh6ng quAn Son
TAy, Hi Tey (50 budc), ...
nAt r. Goi o
le rdm khu6n
vi0n, -{, Y l} c6c
tidp didm nhuhinhv6. R=7. hinhv6. R=7.
Cdch 1.
5ii =5il =e0".
Suy ra Y, I, X
thing hing. Ki
hi6u S,, ld di6n
tich vi6n phAn,
S, lh diOn tich
hinh quat. Sc = S,p(r,,r) * Svp(tnxt
n6n 56 * 56' = Svp(ypX)
so",.n - sr = nR2- 56 = ? * T- 56 = ggm2.
1
(Xem tidp rrang 28)
Di0n tich phdn dinh trdng c6 vd trdng hoa
bang 4 ldn S,o,rr, v) bang
/ t r\
s,= A{Srpw)-saory) = 4+-+l ('4 2) = 56 (*').
Di6n tich L{t b0 tong le
Chd ban tqi Tba sogn
In tai C0ng ty CP in DiOn Hdng, 1B7B Gihng Vo
In xong vh nQp hm chidu thtug7 nlm 2005
Gi5 :4000 ilbng Biin nghin dbng trtrEI trtrtrtr trtrtrtr Hinh l trtr trtrtrtr trtrtr trtr Hinh 2