khOng cdn ddn giri thidt liOn tuc ddi v6i him s6 /(x).
Nhidu ban di cho c6ch girii tuong tu vdi bni toi{n mo
rdng sau dAy:
"Cho m, n ld sd nguy€n dtong, a e (0, l) vd cho hdm
s6' f(x) xdc dinh tr€n [0, 1] vd th6a mdn cdc di|u kiAn
.f(0) = 0,fl1) = t, f(##) = "rur+ (r - a)/(y)
vdi x 2 y, x, y e 10, 11. Chftne minh rdng
^(m3)43
tt- I-
-
' [(. * n)3 - nmz )- i- q2 + a3'
2) Cdc ban sau dAy c6 ldi girii tot:
Ph[ Tho: LA Drtc Anh, l2AL, THPT Phong ChAu,
Nguydn Ngoc Trung,9A1, THm LAm Thao; Vinh
Phic: Nguydn Quang Trudng, Khdng Hodng Thao,
Nguy€nTudn Duy, Nguydn Hodng Hdi, NguyenTi€h
Dilng,l0Al, THPT chuy€n Vinh Phric; Hi NQi' Irrin
Vdn Bdo, l0A2T, THPT chuy€n DHKHTN Hn NQi;
Hi TAy: Nguydn Th€' Anh,9C, THCS Ng6 Si Li€n;
Hir Nam: Trdn Quang Chieh, l0Al, THPT chuydn
Hi Nam; Hii Duong: Vfi Thanh Til, l0Al, THFrf Ke
Sdt,TtdngThA'Nghta, llT1, THft chuyOn Nguy6n
Trii; Nam Dinh: Trdn Thi Hdng Vrin, 10A1, THPT
chuyOn Lc Hdng Phong, TP. Nam Dinh; Hii Phbng:
Nguy€n Qudc Hung,10A1, THPT chuyOn Trdn Phri,
TP. Hai Phdng; Thanh H6a: L€ Ngoc Dat, 10A5,
THPT Luong Dic Bing, Hoing H6a; Nghg An: L€
Trung Son,llT, THP| Nghia Din; Dir Nflng: Pftam
Trong Khdi,10A2, THP| chuyOn Lc Quf DOn; Binh
Dinh: Dri'rg Tdn Phdt,l0Al, THPT PhU C6t 3; Dak
LE,kz Nguydn Dinh Qudc Bdo, llCT, THtrI chuy€n,
Tr*ong C6ng Thdnh, 10T1, THPT Ngd Gia Tu; Cdn
Thoz L€ Dai Hdnh,9A4, THCS Tri N6c.
NGUYEN VAN MAU
*nai Tf0/358. Cho a, b, c ld cdc so' thuc
khAng dm c6 tdng bdng l. Cht:rng minh rang
^tr.@ - rY + r[U +1, -,rY +,1, +1o -6y 2.tj.
Ldi gitii. Do c6c sd a, b, c c6 vai trb nhu nhau
n€n kh6ng mdt tinh tdng qu6t, ta gilh stt a > b I