[中4物理+數學求救!]求物理+數學高手
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b題唔識:'(
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呢題b同c都唔識:'(
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呢題唔識b:'( 本帖最後由 roy624 於 16-12-2013 19:17 編輯
6b.個=你當三橫恆等
a(2+3i)(4-i)+b(2i)(i+5)=6(4+i)+4i
a(11+10i)+b(-2+10i)=24+6i+4i
11a+10ai+(-2b)+10bi=24+10i
(11a-2b)+(10a+10b)i=24+10i
所以,
11a-2b=24
10a+10b=10
用聯立方程計埋佢
就計到a=2,b=-1
10b.
sum of root = A+B=-b/a = -1/1 =-1
product of root= AB = c/a= -8/1 = -8
A^3+B^3
=(A+B)(A^2-AB+B^2)
=(-1)(A^2+B^2-(-8))
=(-1)(A^2+B^2+2AB-2AB+8)<-呢到+2AB-2AB=0對條式冇影響
=(-1)[(A^2+2AB+B^2)-2(-8)+8]
=(-1)[(A+B)^2+16+8]
=(-1)[(-1)^2+24]
=-25
10c用英文學+冇讀phy 6b.個=你當三橫恆等
a(2+3i)(4-i)+b(2i)(i+5)=6(4+i)+4i
a(11+10i)+b(-2+10i)=24+6i+4i
11a+10ai+(-2b)+10b ...
roy624 發表於 16-12-2013 19:09 http://www.nakuz.com/bbs/images/common/back.gif
(c) 叫你用y 整條新式 alpha 3次同 beta 3次係個root
:lol: A^3B^3 =(AB)^3
(AB)^3 =(-8)^3 = -512
y =x^2 + sum of root - product of root
y =x^2 +(-25)x - (-512)
y = x^2 -25x + 512
假設 樓上答案無錯 我都唔太記得 唔該哂咁多位:victory: 本帖最後由 cla991053 於 20-12-2013 15:09 編輯
A^3B^3 =(AB)^3
(AB)^3 =(-8)^3 = -512
y =x^2 + sum of root - product of root
y =x^2 +(-25)x - (-512 ...
傻乂小風 發表於 16-12-2013 22:13 http://www.nakuz.com/bbs/images/common/back.gif
sum of roots 係負數 , product of roots 係正數
x^2 - (sum of roots)x + product of root
所以part c 條式係 y^2 + 25y - 512
仲有條phy
水蒸氣110度降到去100度的熱容量+汽化比潛熱(即係part a答案)=牛奶熱容量,
牛奶熱容量即係mc(dT)啦 dT係溫差, 即係 dT=t-15 (牛奶加熱前後的溫度)
ans係73.46度 , 試下自己寫條式出黎
利申 , 好耐無讀phy 有錯請修正 sum of roots 係負數 , product of roots 係正數
x^2 - (sum of roots)x + product of root
所以part c ...
cla991053 發表於 20-12-2013 14:52 http://www.nakuz.com/bbs/images/common/back.gif
我學戈陣都係甘教
但係近期有人講話 跟返原本條公式個正負 囧
原來我一直岩
比人FAKE鬼左.. 完全唔識
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