37.若log x^2= (log x)^2 ， 則x =
log x^2=2log x
(log x)^2=(log x)(log x)
SO
log x^2= (log x)^2
2log x=(log x)(log x)
log x=2 <<大家除log x
X=100
但係個X點解=1就吳知
比我個方法比大家參考 37.若log x^2= (log x)^2 ， 則x =
log x^2=2log x
(log x)^2=(log x)(log x)
SO
log x^2= (log x)^2
2log x=(log x)(log x)
log x=2
cKonE 發表於 27-3-2009 15:17 http://www1.nakuz.com/bbs/images/common/back.gif
約左唔會少左解咩?
好似#3 個到咁
log x^2 = 2logx
logx(logx-2) = 0
logx=0 logx-2=0
x=1 logx=2
x=100 本帖最後由 ＊林、 於 29-3-2009 18:13 編輯
我想問點計搵幾多個根果d題目...?例如tanx=1/2(度數係0到360)咁.....禁機只係出到一個答案...咁其他答案要點求...?
全部都係用360-返個度數....呢到concept唔係好明...
其實我第1次同人補數時,都唔係幾明....呢個都係後尾諗倒既解決方法.
我地想兩條equation砌埋,令到y 消失, 得返 1條只有 x 是 unknown 既equation
咁隔硬搵方法砌返個 y 入去,令到第3條equation 有個 y 係度 law...
...
【YU】 發表於 25-3-2009 21:53 images/common/back.gif
做就都幾簡單....只係唔明點解要咁做...
係喔....兩根之和同積呢個野係埋outsyll??
我好似未學過咁既野.... 我想問點計搵幾多個根果d題目...?例如tanx=1/2(度數係0到360)咁.....禁機只係出到一個答案...咁其他答案要點求...?
全部都係用360-返個度數....呢到concept唔係好明...
做就都幾簡單....只係唔明點解要咁做. ...
＊林、 發表於 29-3-2009 18:09 http://nakuz.com/bbs/images/common/back.gif
搵多幾個根個個問題
係咪姐係用通解公式? 360- 個個我都聽過 不過唔記得了 用通解我諗一樣呱== 計數機只會計到 -90 至 +90 既度數.
要對返個4 quarter diagram 去搵其他 angle.
我太耐無掂amath,唔知有無out-syl.
印象中CE math應該唔教sum and product of roots
你講o個條都唔駛用sum and product of roots. let the two roots be a and b
(x-a)(x-b)=0
x^2-(a+b)x +ab=0
-(a+b) = sum of root
product of root= ab
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