想問大家一條數,,
ab+bc-ac=0c_U3c V6ABa-c=101
求b~R^R$qv"q2h
要STEPS,,,THX a=101, b&c =0 :D 我都知,,但唔知點得出個ans.,,anyway,,THX a=101-c
ab+bc-ac=0DK;T#h+}2K*i[)t
b(101-c)+bc-c(101-c)=0
101c-bc+bc-101c+(c*c)=0
c*c=0(e'g Vo;Ln1G\
c=0
a=101-0V6d9x(E!Pmr|^x
a=101
ab+bc-ac=02|1{&V-gXV1y
a=101
c=0
101b + 0*b - 101*0=0
101b=0CJ3XI'N5H+Q{
b=0 [quote]Originally posted by [i]ch.chak[/i] at 2008-1-17 09:38 PM:$G4z'NN?[|w
a=101-cN%|gv&nb [@
ab+bc-ac=0;xL3g(k,|d-T
b(101-c)+bc-c(101-c)=0:O\.| K ^6Kz4G \
101c-bc+bc-101c+(c*c)=06E$N)J-D'HS
c*c=04v!N,p4rzhi
c=0
b!c]TdhW `2O Z'M
a=101-0$J]R-x5W0Q;nT$H_
a=1017^jV8Qo\
ab+bc-ac=0
a=101
c=0:ugPN&z.W A
101b + 0*b - 101*0=0
101b=0
b=0 [/quote]
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對不起
請容許我指出錯誤:_f SH"a4M\2s
在一開頭
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[color=Red]a=101-c[/color](原本是a-c=101,移項應該是a=101+c)
ab+bc-ac=0.hy~@u8W
[color=Red]b[/color]([color=Red]101[/color]-c)+bc-c(101-c)=0
[color=Red]101c[/color]-bc+bc-101c+(c*c)=0tAzz^(}
c*c=0nD4P)^b)U.p
c=0E Ul(PMPss9k$f.s
5X v%Je4SVR!c#]p
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:
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對不起
請容許我指出錯誤
(@&k_XH!I,@(r
在... [/quote]
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冇留意錯左tim [quote]Originally posted by [i]托迪仔T[/i] at 2008-1-17 07:42 PM:"Ud8v/|EhY/zowa
a=101, b&c =0 :D [/quote]
ab+bc-ac=0$N3QP To2}7A kWm
a-c=101bN9G}E:JC tM.ff
求b
咁玩法...如果c係-101...a同b=0 都得架wo:D [quote]Originally posted by [i]sakura310[/i] at 09:58 PM:
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對不起'dz No t |S7_FL}/y
請容許我指出錯誤
在... [/quote]
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咁你又吾去計;);):P:P [quote]Originally posted by [i]playbr2[/i] at 2008-1-17 11:58 PM:*{1QHcRanp.Ux
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咁你又吾去計;);):P:P [/quote]
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playplay你串我?:mad::noway::fight::angry:(表情符號好好玩的說:D)%PTD@ m`s _'a
咁你呢~你又唔去計?:dev::dev:,V'\!H v*Q;|4H
等了這麼久也沒人貼答案出來
那麼讓小生物來獻醜了:redface::redface::redface:
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手寫關係,所以上傳圖片先了(懶得去打)X%{ipb&H
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由於題目沒有說到a,b和c是甚麼數,我暫且假設係整數黎做(光是實數的話...太沒意思了...)Ao#p+j7jN"vv J4`)g
如果是實數的話,那麼請看到左邊2/3就可以了,中間和右邊是整數的解集(次序:左>中>右)
用的不是甚麼古怪的方法,應該好易睇得明oe8sQfUT
這算一種對付三個未知數,但只有兩式的求整數解方法.pQ`DZe)hB
有不明的話可以提出:jCI)V%A
不過我要訓醒頭覺先回覆到,好累的說(脫力中...)
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[[i] Last edited by sakura310 on 2008-1-18 at 12:12 AM [/i]] [quote]Originally posted by [i]sakura310[/i] at 12:08 AM:n3x;g me.c U
playplay你串我?:mad::noway::fig... [/quote]
乜咁快手ㄚㄚㄚㄚ:D:D:D:D
個答案可以咁.....
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1.ab+bc-ac=0Wm6Jm;tmY
a-c=1014TQg9I'{ `4[ z%~l
b=ac/(a+c)=(101c+c^2)/(101+2c)xkit-M
設c=101n*Obp,[$i?/[9s`[Y
101n代入co|6UV&e
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[101^2*n+(101n)^2]/(101+202n)
=[(101^2)n(n+1)]/[(101)(2n+1)]3r;P:`$t_:PT7c,Q
=[101n(n+1)]/(2n+1)
因為a、b、c是正整數
所以n是正整數
所以[101n(n+1)]/(2n+1)是整數"C7H-mrg#F
2n+1=101(剩下的2n+1=n或2n+1=n+1,n沒有整數解)
n=50
a=5151 <--a-c=101
b=2550 <--[101n(n+1)]/(2n+1)
c=5050 <--c=101n| ^&d(b?0P#c
答案:b=2550 Filename: DSC01158.JPGUJ K6OG.@%_&]Ed
Datetime | Downloaded by | Counts;bJ,ngX*y
2008-01-18 00:25:24 | 阿感 | 2
2008-01-18 00:24:20 | playbr2 | 2
2008-01-18 00:22:02 | 但丁 | 2,Iv&MtM:B+q)E:M E"e
點解大家都down兩次? XD [quote]Originally posted by [i]sakura310[/i] at 12:27 AM:,papMtVj~.nA.~
Filename: DSC01158.JPG
Datetime | Downloaded by | Counts.@0J~fz1c)Pa'jHU
2008-01-18 00:25:24 | 阿感 | 23NOSv|$A@
2008-01-18 00:24:20 | playbr2 | 2
2008-01-18 00:22:02 | 但丁 | 2
點解大家都down兩次? XD [/quote]$t!@o/u4Yf
我第一次開睇左2秒就close 左:P:P
之後DL (就变成第二次) [quote]Originally posted by [i]sakura310[/i] at 12:27 AM:
Filename: DSC01158.JPG5Q?/S(Gc ](^
Datetime | Downloaded by | Countst5~~ZVqb
2008-01-18 00:25:24 | 阿感 | 2
2008-01-18 00:24:20 | playbr2 | 2
2008-01-18 00:22:02 | 但丁 | 2&}U%~ itg2a8^S
點解大家都down兩次? XD [/quote]
快d捉我錯處:D:D:D7S8AA_n'P/[k
話吾定我都打錯 + - 符號
係電腦打答案...的確幾煩...又哂時間...:giveup: 捉錯處就唔敢當~2ZNfp ZtHw0VB
不過,c=101n哥度(解除n係正整數的限制,只是整數)!kPw%]#b`
就一下子限制左c一定要係101的倍數(好像看懸疑片,突然劇情說出一些事前沒提及過的線索,不爽~)
知道{101,0,0}和{5151,2550,5050}係答案的話,當然沒問題 V(s8X*Lj}}J
但原先是不知答案,所以唔知有無失根
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有時見到題目都感到有點不爽F@/i_HJC
題目所求的答案是整數,正整數,有理數,實數等等應該說清楚%\,H8}ELb8KZ
有些題目,整數解和正整數解分別好大的說,要找出整數解集有時可不是件易事= = 冇答案ga....
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2條equation solve 唔到3個unknown ga.... [quote]Originally posted by [i]cutec[/i] at 2008-1-18 08:26 AM:%s$z.V6Sf `M5@Z
冇答案ga....Th%s,e&j'F9S5v
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2條equation solve 唔到3個unknown ga.... [/quote]
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agree "^&A7F+Z i
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2 equations 2 unknows
if 3 unknows there should be 3 equations
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make it simple 4q2Bt)pB@~7hb2} _
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say
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a + b +c = 3eW1H/Y[bS#@!~h
+nr3zev0{Y
a+b = 2