: (IF ,KF)(mod m) (vi EF KF).
cdc thi nghi0m tr€n d6y ddn, nguoi ta thiy ring: Ngodi tAn s6,6 (am co-tAn s6 dao dQng
ring: Ngodi tAn s6,6 (am co-tAn s6 dao dQng
fd ru, c6c dao dQng c6 tdn sd 2fo,3fo,4fs dCu
"thamgia,56
thi nghe r6t y6u.
X6t di€u kiQn: Cirng vcri Am fr trong thang nhpc phii c6 Am 3fi)- Cing c6 ngtria ld cin c6
?
?rm * fn, ffong khoing (fo;zfi. Ngodi s6 m ra,
z- -
1
ta phii tim dugc sa t 1t < m) sao cho fi,:;f,
3DiLt A : loglfs ta c6 log1fi, : log21 + A. DiLt A : loglfs ta c6 log1fi, : log21 + A.
Suy ra phdi tim c5c sd nguy6n m vd' k sao cho
3k
loe:i :
- mt. (4)
^a
Di6ukien (4)tuong.lumg zi = I ,2 e*-* : 3*.
Ei6u kiQn ndy kh6ng th6 thoi min vi v6 tr6i
chin, v6 ph6i 16. Nhu vQy kh6ng th6 tim duoc
hai s6 nguy6n k vd m
^thod
mdn (4). Trong
{1
thang log kh6ng c6 Am
i,fo. Q"arg (f;1"f0) Soi
ld qudng ndm hodn todn (ho{c quang ndm dtrng). Nhurg.cAn phii qiir lai tinh "ddu" cira thang
nhac d6 khi chuy6n giai diQu kh6ng bf mdo,
3
cdn 6m "hoin toirn" c6 tAn s6 dtng ;/0 thi
dugc thay bing mQt 6m c6 tAn s6 dao tlQng gAn nh6t ch6p nhin rlu-o. c v6i 6m hodn todn
(d6 chinh ld f tuong "cii ti6n" c'ia AngdrAVecmayo).Ngtria ld tim sO fruu 1i L gAn ai^e Vecmayo).Ngtria ld tim sO fruu 1i L gAn ai^e
,?
vcri s6 vd ti logz ' sao cho sai s6 t6n s6 trrong img "-2
nh6 hon lHz dA tai ta khdng nhQn thay du-o. c.
1:
,l
NhAn thAv ,r = Q. 583 edn rlfing logr j dat d0
' --'-" *--J 12 "- 2
chinh x6c 0,002 (1Hz img vdi 0.004 tr6n thang
log). L6ry m: 12,,ta dugc thang nhac d6u 12
6m, dm thir biy rdt 96rr v6i qudng n6m hodn
todnjfo. Ta c6 bang sau:
Thans ..._-.O nhac 12 bdc d6p tme tdt cdc ydu cdu
. \ t-
ctra chring ta dd ra. Logarit ti s6 tAn s6 cua hai
{
Am li6n nhau logzl+ 1u6n bing sO t<hong O6i
"- Ji
1
* . fi s6 tAn so dao dQng cua hai dm 1i6n
l/.
nhau trong thang nhac 1u6n bdng mQt sO khOng
1
a6i Zi gin dirng voi s6 htu ti 1,059. Khodng c6ch gita hai Am aV ru | cung, khoAng hai
nua cung ggi ld m6t cung.
Nhqn xit.-Thang nhac dAu 12 bfc niry, chia
thang nh4c bay bflc (l). Lay chir dm Do' c6 tAn s6 26zllrvd qu6ng t6m Do2 c6 tAn s6 szlHr.
Ta c6 bdng sau:
(i : 0, 1,2,...,11,12)
Ngodi 7 dmcobannong quangt6m (Do1-Do'),
ta cdn 5 dm php trong tQp hqp vria du 12 bflc
cria thang. Chirng duqc ki hiQu bing c6ch th6m vdo d6u thang (#) hoqc d6u.gi6ng (b) b6n cpnh
circ 6^mco ban. Vi dUl : Do'o holcf3: Mi'o . . .
Tir thang nhqc 7 b4c kh6ng ddu, sau khi bo sung them 5 im phu ta c6 thang nhqc ,12 bdc
oe"' (Do, Do#,
-Re,
Re#, Mi, Fa,- Fa#, Son,
son#, La, La#, si, Do), hoflc (Do, Reb, Re, Mib,
Mi, Fa, Sonb, Son, Lab,La. Sib. Si, Do1.
(Ki sau ddng ti6P)
.0. r1 a t::3:.r: :r,4.r: 5 6 loefr- loe2fo 0 1 a a2 nJ t24 5 t2 6 a 1 8 9 :10 I1 t2 loert- loe2fo 7 n 8 i n9 n10 a11 I
Am Do' r,Rsr.:: Mi, Fal'
Tdn s6 fi .lo-262 2'76 .J)- 294 .13 - 309 .14 - 330 J5 349 .t6 366,5 loerfi 8,033 8,1 14 8,1 98 8,217 8.365 8,448 8,531 logzf 1oe,f,, 0 0,083 0,16-t 0,250 0,334 0,417 0.500
.r,Am sof .I;A' sr D*
TAn s6 fi 392 .18 - 41r,6 fn- 440 /ra: 462 .l1t - 494 l12- 523 loei; 8,615 8.691 8.78 r 8,864 8.948 9.031 logzfr los.f" 0.5 83 0,667 0,750 0,833 0,917 t,000 TCINN HQC