娛樂滿紛 26FUN » 吹水版 » 想問大家一條數,,

SKII999 發表於 2008-1-17 07:26 PM

想問大家一條數,,

ab+bc-ac=0
&F5b!?5S9yQtt           a-c=101.L D HI*ciX9S
          求b
-[X+t"nAIyj 6Et4Qx|8b
          要STEPS,,,THX

托迪仔T 發表於 2008-1-17 07:42 PM

a=101, b&c =0 :D

SKII999 發表於 2008-1-17 07:52 PM

我都知,,但唔知點得出個ans.,,anyway,,THX

ch.chak 發表於 2008-1-17 09:38 PM

a=101-c
.f o/q~2u^^[$S ab+bc-ac=0
A1uE4VP5n A b(101-c)+bc-c(101-c)=0
s7^ `H Y"| 101c-bc+bc-101c+(c*c)=0
? G&{M] c*c=0 wR1Um6N1F0eM
c=0
8YEoiuWV f6R4y!n)R
a=101-0
:p @ _7m}\ a=101
;m.\}w:Zy
Grvd\BW&x8a ab+bc-ac=0
.oC:j\sb a=101
v7O~PU
N!PNX c=0
T5D%gy!H$zT 101b + 0*b - 101*0=00P0y.t L VO-{1?T
101b=0
){N2mV#@2?T b=0

sakura310 發表於 2008-1-17 09:58 PM

[quote]Originally posted by [i]ch.chak[/i] at 2008-1-17 09:38 PM:
J.[#OU9IVz"^;I
a=101-c
'b-Vj0iImB7g`
D ab+bc-ac=0 w[%C\.`.b2`V
b(101-c)+bc-c(101-c)=0Kx1\Z$J8S!e
101c-bc+bc-101c+(c*c)=0
)aV k$c*{Ae.FAv c*c=0
;uZu|g"Y\2| c=0
cT6P/NPI0j .? \7JHI;Vl
a=101-0
y:U5nB k$@8q0h)x a=101
(`8d/z
@SzDs
M:GL%nx'Q PK&Y ab+bc-ac=0
i1T8{)T;i/~4e4MC a=101
o1f)G:ME'@7r*N c=0
5ml|T\NI
wu 101b + 0*b - 101*0=0o3s+Z:qD
C
EE
101b=0^!P~HR{ F
b=0 [/quote]
_6}/O0{g
^G;ai;?1K 對不起
O&S7CK6zC4O.c\7^ 請容許我指出錯誤z1E'_:eeJ$b1x

#[8_F/Y.dH!?'d 在一開頭|*Y+ap'@ri8cU

n.wLK
o w_ I [color=Red]a=101-c[/color](原本是a-c=101,移項應該是a=101+c)W{4DH#N~%kF#u(gK.f
ab+bc-ac=0eSs&O']ZIRb
[color=Red]b[/color]([color=Red]101[/color]-c)+bc-c(101-c)=0P4G*CQ3^^)h
[color=Red]101c[/color]-bc+bc-101c+(c*c)=0
iZCHY hx!|K c*c=0+rm };Ezu\
c=0
6x u-p k+m1M,JY'~ :m;}Dh1Mgw5[
基於以上紅字的地方,其餘的地方我認為沒必要看了

ch.chak 發表於 2008-1-17 10:53 PM

[quote]Originally posted by [i]sakura310[/i] at 2008-1-17 09:58 PM:
W3xchPu}U
|)`QGY(ZO

myu\C(VO 對不起
D8c.v.l ]`4IQ 請容許我指出錯誤0Q3q pW;C+}i%n
X7S
z4H`*[H!v
在... [/quote]#}J,uwiL
係bolC$hsD
冇留意錯左tim

呀俊 發表於 2008-1-17 11:00 PM

[quote]Originally posted by [i]托迪仔T[/i] at 2008-1-17 07:42 PM:
"m}Ygb0G eaK a=101, b&c =0 :D [/quote]hg\7o1i6p4Z
ab+bc-ac=0T.J%M?n?
          a-c=1019d(i5P?i G
          求b
9~h|x%tG&R,|CR5W 咁玩法...如果c係-101...a同b=0 都得架wo:D

playbr2 發表於 2008-1-17 11:58 PM

[quote]Originally posted by [i]sakura310[/i] at  09:58 PM:
Y] JDaR*}l V.dX;is5owR
A&_*BO S+yJ.T0h)Zw
對不起
.Wnc a9r$a8@#O 請容許我指出錯誤@ e5Q|wh
D,x.t
E0TM6i9w
在... [/quote])a}HYc.KD"V
SW"L0X N~
咁你又吾去計;);):P:P

sakura310 發表於 2008-1-18 12:08 AM

[quote]Originally posted by [i]playbr2[/i] at 2008-1-17 11:58 PM:%I8aaqc-B^_+v
Dg^V+lu

g`:{_"YKk!zJ:Z 咁你又吾去計;);):P:P [/quote]
-UrY%|Z
O A.u6bQ"@3m
v P$v
playplay你串我?:mad::noway::fight::angry:(表情符號好好玩的說:D)
1z6f9C"w:{4q
iXr/\&oEN bM 咁你呢~你又唔去計?:dev::dev:"_S1{y4p!r&q"^ z*{#[

2iw:y"y#P%@ 等了這麼久也沒人貼答案出來
8I5K E"PGq_ N]@Mk6a
那麼讓小生物來獻醜了:redface::redface::redface:
lDW+C:|/h l*j1u"W%s$d
手寫關係,所以上傳圖片先了(懶得去打)G"UG'DX_L

p3V5Mm'm*j 由於題目沒有說到a,b和c是甚麼數,我暫且假設係整數黎做(光是實數的話...太沒意思了...)
5F Hi
}-iNa+cN2f yu5d.gyj i7W
如果是實數的話,那麼請看到左邊2/3就可以了,中間和右邊是整數的解集(次序:左>中>右)
"l&k2r*B
@;J HD Z\U,P&}3Rb}B
用的不是甚麼古怪的方法,應該好易睇得明

~_,O`x3r .b Ef!aO%z;?0y}#U
這算一種對付三個未知數,但只有兩式的求整數解方法f`itz
Q,e3g_4P!Tv Ud'U
有不明的話可以提出
M
r.Y$ne `pa(xzqH 2y/]qI.UHQdo
不過我要訓醒頭覺先回覆到,好累的說(脫力中...)%e(V f/OS4X

-[ wK&]'Sf \d-| [[i] Last edited by sakura310 on 2008-1-18 at 12:12 AM [/i]]

playbr2 發表於 2008-1-18 12:21 AM

[quote]Originally posted by [i]sakura310[/i] at  12:08 AM:
_nlq!D
^&k&Z^Uh/d E+n&x'X'r
playplay你串我?:mad::noway::fig... [/quote]iZO5@4XrW/|pM,H[

/H2Zp Mp X 乜咁快手ㄚㄚㄚㄚ:D:D:D:D
jm+_2c.fu*w _ *qf](y9HGh
個答案可以咁.....8K%ikS7^c
t^3D$C!|6P
|2]\#y&F
1.ab+bc-ac=0xD1^-n4Y:KF8L8V0j
a-c=101
&[1r1I!c!l b=ac/(a+c)=(101c+c^2)/(101+2c)L
~\&Ww(n7h qfJ
設c=101nAotFeIa-i
101n代入c
}SE2p@O0Vc #VReT#l7P,?$H
[101^2*n+(101n)^2]/(101+202n)
'N1@i_KY+GXD =[(101^2)n(n+1)]/[(101)(2n+1)]
`)h8H&o'OjmF_c)D-A =[101n(n+1)]/(2n+1)
CvS,J4H-id rF4b @h1V#pN
因為a、b、c是正整數z i(W)P;c-nd
所以n是正整數
7j:E/U'p5^C1qQ 所以[101n(n+1)]/(2n+1)是整數 [&p7[%wa1jG'y4{
2n+1=101(剩下的2n+1=n或2n+1=n+1，n沒有整數解)
cm&jTQ`7n,Yb.{ n=50(NC)j&IqEu r#Ka
a=5151  <--a-c=101H0@P4^U*bE|7}
b=2550  <--[101n(n+1)]/(2n+1)
%G)~(c g#t
t,G c=5050  <--c=101n Wc v5q!iEg
答案:b=2550

sakura310 發表於 2008-1-18 12:27 AM

Filename: DSC01158.JPG nDMK^:O
Datetime | Downloaded by | Counts
KI(Y"O/cFz'A
HG 2008-01-18 00:25:24 | 阿感 | 2
/N,X/Y'mL Eq@ 2008-01-18 00:24:20 | playbr2 | 2
N.B2P&X3n B 2008-01-18 00:22:02 | 但丁 | 2
S"i\*_2Ok.a6Q mMa1gL'L
點解大家都down兩次? XD

playbr2 發表於 2008-1-18 12:30 AM

[quote]Originally posted by [i]sakura310[/i] at  12:27 AM:
0h"n!uH@%OVq Filename: DSC01158.JPG,Sn`` Y7nz
Datetime | Downloaded by | Counts$ll;_1C&Yv
2008-01-18 00:25:24 | 阿感 | 2!|wh{T!z
2008-01-18 00:24:20 | playbr2 | 2
;G2wP@(K.I:A&P 2008-01-18 00:22:02 | 但丁 | 2,LA)Lht~F1y

'U~M8_!`n 點解大家都down兩次? XD [/quote]
Q8B"jY} RVK3\
ks:`$h-V?#|*T 我第一次開睇左2秒就close 左:P:P
Y5d|
{)Qy 之後DL (就变成第二次)

playbr2 發表於 2008-1-18 12:34 AM

[quote]Originally posted by [i]sakura310[/i] at  12:27 AM:
M(u#jh(yJK8? | Filename: DSC01158.JPG
D?%oE g n6OQ,s)F Datetime | Downloaded by | Counts1H!j|/Q9{~ z
2008-01-18 00:25:24 | 阿感 | 2.x"By!v-m7`s8c
2008-01-18 00:24:20 | playbr2 | 2
/?8W5W |swG 2008-01-18 00:22:02 | 但丁 | 2
1pj"X n8d"J|Z
EK7Y+Sp"OO
點解大家都down兩次? XD [/quote]zt6fP-wClYO!`

,c+V}c)Q\l 快d捉我錯處:D:D:D
hO'dC0E%W 話吾定我都打錯 + - 符號
b*YhC?Z.JZ 係電腦打答案...的確幾煩...又哂時間...:giveup:

sakura310 發表於 2008-1-18 06:47 AM

捉錯處就唔敢當
+okEeHzK 不過,c=101n哥度(解除n係正整數的限制,只是整數)
)xlX.d3G 就一下子限制左c一定要係101的倍數(好像看懸疑片,突然劇情說出一些事前沒提及過的線索,不爽~)
3~%_+]$@ f 知道{101,0,0}和{5151,2550,5050}係答案的話,當然沒問題&I}(wj od
但原先是不知答案,所以唔知有無失根
.s^T{x]4fU
'xx D@j0f)z 有時見到題目都感到有點不爽
f.e7\SN 題目所求的答案是整數,正整數,有理數,實數等等應該說清楚
Z
\7S wI'n]l
有些題目,整數解和正整數解分別好大的說,要找出整數解集有時可不是件易事= =

cutec 發表於 2008-1-18 08:26 AM

冇答案ga....
G B"Y.b5C(o Y.Vk(t 'n4@q@P(Nh
2條equation solve 唔到3個unknown ga....

Azuma 發表於 2008-1-18 08:56 AM

[quote]Originally posted by [i]cutec[/i] at 2008-1-18 08:26 AM:
+Xu?!S&Dee 冇答案ga....
&\4Grq#@:}1j !C dp"FKn#g5ZmV
2條equation solve 唔到3個unknown ga.... [/quote]7Z3n,yM+JG)hDE5``;k

{8W,b%] t-?I#KE agree ON1a-GcF9^
)BY!h#x J
2 equations 2 unknows
`%o1es%[b%G
tl5EM i#BKt if 3 unknows there should be 3 equations J[*s6j*V

1w:fYV\;Bb)T make it simple
2{2q:];Q7v ,EJ8q2H`:M v
say $QF&m/UM5oJ3K?lg
bm\$y(v z5s2h%Z)d+z
a + b +c = 3h b a2F _x9E.LF0~

6H+S`"Q1jj5p&Z a+b = 2 oAgW^"o/Z
9H,m(S(rp
then c is 1
8J Ft#^8Z/C 8Ugn,R$p
a = 2 - b
#Z.I9S-t%yh T}p
!c&^;uxR)z0}w2e so 0 = 0
0?A}-CL[ -Z4Xc4j%]
:giveup:

sakura310 發表於 2008-1-18 10:22 AM

[quote]Originally posted by [i]cutec[/i] at 2008-1-18 08:26 AM:
;e1AAd!gk;u$ru| 冇答案ga....(TEd/]\So

2Km6r!gr 2條equation solve 唔到3個unknown ga.... [/quote](Jp(~)g{G/G
A,YaL-Gpelq"F2K}
此言差矣~
F:L,Q y3tBhv
y,EB(Y \*M[ h*Yu 2條equation solve 唔到3個unknown gaC B^-j|(c&D'eV
還欠一個條件,就是3條equation都是linear independent(線性無關)的
(JE:T1\x&yZ t;Zj*]#Fl
簡單點說,多元一次方程就是線性方程的一個例子
BU;R:A^,mG 在這情況下,當然是想求n個未知數,至少要用n條線性無關的方程w&z.[L8k;^

G
uldVY
如果不是線性的話,有機會1條方程解3個未知數的(這不是每次都可以的啦~)
$w6`Aq`h^E 例如 x^2-2(x+8y)+17+4y^2+z^0.5=0 就只有唯一整數解(B)f wf+A
有興趣就解解看:sleep:
#N&r;\p3Q;q#Qe 不懂的話就問playplay,佢會知答案:dev:

playbr2 發表於 2008-1-18 02:47 PM

[quote]Originally posted by [i]sakura310[/i] at  10:22 AM:Xv9xo7[k
.c
]"k8X pP0V.j

c7wcE#NOXm2h 不懂的話就問playplay,佢會知答案[/quote]
a.`'[IR{b
.?(q/f.E5jyPw*xYi :cry::giveup::giveup::giveup::giveup:

playbr2 發表於 2008-1-18 02:57 PM

[quote]Originally posted by [i]sakura310[/i] at  06:47 AM:
&?3S
ero~
~
eh 捉錯處就唔敢當$ElKG8i+Qp1W
不過,c=101n哥度(解... [/quote]
%D6m8g5x#^a
k:E:_h!L*e C[;m 都係睇餸食飯姐 , 無理由因為題目冇同你假設就下下大包圍架(\'S&ybOp
反而適當地調節一下 , 咁會理性好多
d U&_FwL 就好似隻game 由12粒珠 加到13粒珠咁
6?A4f6Z:q 當''堂''好玩哂:P:P:P2F e#nJX@
X

^HH@vCT7c p.s. 求''堂''字正寫:agree::giveup:

QuiGonJinn 發表於 2008-1-19 03:49 AM

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