想問大家一條數,,
ab+bc-ac=0pSH2em[Ca-c=101
求b,Eh:K3e,fi-s
要STEPS,,,THX a=101, b&c =0 :D 我都知,,但唔知點得出個ans.,,anyway,,THX a=101-c\^o+y.j%_
ab+bc-ac=0
b(101-c)+bc-c(101-c)=0
101c-bc+bc-101c+(c*c)=0X/`D*[zX0n
c*c=0^1E]2N&T4L
c=0
K0f7]NXS TMND
a=101-0
a=101
ab+bc-ac=0#U\.J'U4b)xJZ
a=1014b{]\!H.x-?0u
c=0
101b + 0*b - 101*0=0wg{t!|b!iR
101b=0v7pd,\L_mmm$?8O@V
b=0 [quote]Originally posted by [i]ch.chak[/i] at 2008-1-17 09:38 PM: T-l&t(F^;E^lA2vm
a=101-c dqM3U)w^#W
ab+bc-ac=0
b(101-c)+bc-c(101-c)=0
101c-bc+bc-101c+(c*c)=0
c*c=0
c=0_2t"W8aGx~n6@
%_AIaB|'Am+b A
a=101-09G%s] p(S[.C7w
a=101L}N(kZ(E
ab+bc-ac=0
a=101*NPv@ _S
c=0
101b + 0*b - 101*0=0Ch1R\y|h? ux+?}
101b=0
b=0 [/quote]GM#t[ y!M9Jy
.R,A3B%HXT Jf
對不起yY.x ~ts-@;R$~
請容許我指出錯誤
No+S hG\$cB
在一開頭
[color=Red]a=101-c[/color](原本是a-c=101,移項應該是a=101+c)
ab+bc-ac=08R)d8d3w7q [
[color=Red]b[/color]([color=Red]101[/color]-c)+bc-c(101-c)=0
[color=Red]101c[/color]-bc+bc-101c+(c*c)=0Z.A;Tp}QI7|
c*c=0.NE0e ]7c!h+NQ#BD
c=0
/j7u_ZC [2t#g{,KJ
基於以上紅字的地方,其餘的地方我認為沒必要看了 [quote]Originally posted by [i]sakura310[/i] at 2008-1-17 09:58 PM:
4]|"d"G u
+tH}/T5BTY
對不起
請容許我指出錯誤
%K'Isf-qQ-P*l
在... [/quote]|;R5dkR!A F
係bo4wh LSR
冇留意錯左tim [quote]Originally posted by [i]托迪仔T[/i] at 2008-1-17 07:42 PM:
a=101, b&c =0 :D [/quote]xXw#vI,tw
ab+bc-ac=0~u1K|n8Z
a-c=101
求bQ na.XR1e7h
咁玩法...如果c係-101...a同b=0 都得架wo:D [quote]Originally posted by [i]sakura310[/i] at 09:58 PM:G8V\pJp8E"}?I
對不起
請容許我指出錯誤
-ar |!_`7M2J*mA_(W}
在... [/quote]1n/@/LQ:\&wxKD*]
咁你又吾去計;);):P:P [quote]Originally posted by [i]playbr2[/i] at 2008-1-17 11:58 PM:)j1tBz/NIK
(G$b(w/R4Tkwx
咁你又吾去計;);):P:P [/quote]~"Jr P No9^ u
playplay你串我?:mad::noway::fight::angry:(表情符號好好玩的說:D)-T3Q3Hf-Bq"a
咁你呢~你又唔去計?:dev::dev:O9lT$M9H"E*vZ
i'~;N viI3j2S"Z
等了這麼久也沒人貼答案出來+I/Rl&Q-KIH
`m+[8E&`P}o
那麼讓小生物來獻醜了:redface::redface::redface:Xf-b{$t)B b&{1?Py
'\O8v5CP+IeW
手寫關係,所以上傳圖片先了(懶得去打)R`){o2P^5lxJ5B
由於題目沒有說到a,b和c是甚麼數,我暫且假設係整數黎做(光是實數的話...太沒意思了...)
s*OG!tM._/l-w~Y
如果是實數的話,那麼請看到左邊2/3就可以了,中間和右邊是整數的解集(次序:左>中>右)X+_y7B!w
用的不是甚麼古怪的方法,應該好易睇得明
u_(OI)k[*}Cl
這算一種對付三個未知數,但只有兩式的求整數解方法{&D.G*I/^
有不明的話可以提出
I%I0P"yO)A{)O
不過我要訓醒頭覺先回覆到,好累的說(脫力中...)&xv]weq^|
[[i] Last edited by sakura310 on 2008-1-18 at 12:12 AM [/i]] [quote]Originally posted by [i]sakura310[/i] at 12:08 AM:(@^f KO4Mr r
playplay你串我?:mad::noway::fig... [/quote]
v%G6|8ZE
乜咁快手ㄚㄚㄚㄚ:D:D:D:D
Bvf,^hVq
個答案可以咁.....
il5w:iB(t"X+k)b c
1.ab+bc-ac=0"XC(U/v7Wp2V
a-c=101
b=ac/(a+c)=(101c+c^2)/(101+2c)N;Giy S[0X
設c=101n
101n代入c
e6TX6d%uN,q
[101^2*n+(101n)^2]/(101+202n)"[+{k%P,Z/@K
=[(101^2)n(n+1)]/[(101)(2n+1)]
=[101n(n+1)]/(2n+1),v0nN;j7oJc Z
,A#uZ0pC~%FecL5F
因為a、b、c是正整數
所以n是正整數4vx2K|~#?9x2U!bB
所以[101n(n+1)]/(2n+1)是整數
2n+1=101(剩下的2n+1=n或2n+1=n+1,n沒有整數解)N*aU/ALN%g"W3c!V6\
n=50}0Y1p_,A
a=5151 <--a-c=101
b=2550 <--[101n(n+1)]/(2n+1)
c=5050 <--c=101n
答案:b=2550 Filename: DSC01158.JPGR6P4yO*ZV
Datetime | Downloaded by | Counts
2008-01-18 00:25:24 | 阿感 | 24rtn2n}:`.~.O0^h
2008-01-18 00:24:20 | playbr2 | 2b"_*mH6b#i kE
2008-01-18 00:22:02 | 但丁 | 2
UM*dje _'^6M
點解大家都down兩次? XD [quote]Originally posted by [i]sakura310[/i] at 12:27 AM:
Filename: DSC01158.JPG)L} k1w&F(B
Datetime | Downloaded by | Countsf*\|-a1XP2\
2008-01-18 00:25:24 | 阿感 | 2
2008-01-18 00:24:20 | playbr2 | 2^J4J~a!H
2008-01-18 00:22:02 | 但丁 | 2R%r.`1j1[ _
*u1|um?9N o
點解大家都down兩次? XD [/quote]
我第一次開睇左2秒就close 左:P:P
之後DL (就变成第二次) [quote]Originally posted by [i]sakura310[/i] at 12:27 AM:iQ$[8C#f;C c#D
Filename: DSC01158.JPGZc*tB5h3Y
Datetime | Downloaded by | Counts
2008-01-18 00:25:24 | 阿感 | 2
2008-01-18 00:24:20 | playbr2 | 2#B^Qo)c2I;D7TK~)GQ
2008-01-18 00:22:02 | 但丁 | 2r2ZZ/u+u"ylL
kl,VR2_?[ Mz
點解大家都down兩次? XD [/quote] kY#{vF?*g0[0fK
快d捉我錯處:D:D:D~I3A"f&i:s
話吾定我都打錯 + - 符號"^*?Oj2g/|(L
係電腦打答案...的確幾煩...又哂時間...:giveup: 捉錯處就唔敢當
不過,c=101n哥度(解除n係正整數的限制,只是整數)
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~)EXX)Yj&b
知道{101,0,0}和{5151,2550,5050}係答案的話,當然沒問題
但原先是不知答案,所以唔知有無失根
有時見到題目都感到有點不爽
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Q]i!@z
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= = 冇答案ga....
2條equation solve 唔到3個unknown ga.... [quote]Originally posted by [i]cutec[/i] at 2008-1-18 08:26 AM:lVx"O!~'kX:H
冇答案ga....kRm_ BxA!eC s
\dp7v(mX#k r+a z:h
2條equation solve 唔到3個unknown ga.... [/quote]
agree (L~!I1M~T8v#i0ej
2 equations 2 unknows
1_ CO/|y/b
if 3 unknows there should be 3 equations /H6`]-fpP7F9b!Z:L
make it simple zo Co6N;aL
_[;o(w4@(N"aY&nx
say $[MbI\ {D
a + b +c = 3
a+b = 2
uS0P%oK*co!c,?
then c is 1
M$ITi9I EK7U+W
a = 2 - b
1JJv k*q
so 0 = 0 ZLLE"N} Z
:giveup: [quote]Originally posted by [i]cutec[/i] at 2008-1-18 08:26 AM:qJ9oca5N\uu{)D
冇答案ga....
|if/SNM$OL
2條equation solve 唔到3個unknown ga.... [/quote]+V/W9Rzx
此言差矣~QB,lZ X,D~$Y/Y
2條equation solve 唔到3個unknown ga
還欠一個條件,就是3條equation都是linear independent(線性無關)的
簡單點說,多元一次方程就是線性方程的一個例子
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f?fKOGF
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~);KMw1ad7pT2|\i
例如 x^2-2(x+8y)+17+4y^2+z^0.5=0 就只有唯一整數解G&Dh%enr
有興趣就解解看:sleep:
不懂的話就問playplay,佢會知答案:dev: [quote]Originally posted by [i]sakura310[/i] at 10:22 AM:X^;G)Dko
不懂的話就問playplay,佢會知答案[/quote]
@AW O)P0M5o
:cry::giveup::giveup::giveup::giveup: [quote]Originally posted by [i]sakura310[/i] at 06:47 AM: a m;I^jB'H,}\$Ec2\
捉錯處就唔敢當
不過,c=101n哥度(解... [/quote]5J7LJ-[2a K
r#S+JfINNa"TWB
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
反而適當地調節一下 , 咁會理性好多
就好似隻game 由12粒珠 加到13粒珠咁
當''堂''好玩哂:P:P:PL;D/oKwT
p.s. 求''堂''字正寫:agree::giveup: **** 作者被禁止或刪除 內容自動屏蔽 ****
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