maths

2007-12-17 3:02 am
(logx)^2-log(x^2)-3=0

回答 (2)

2007-12-17 3:13 am
✔ 最佳答案
設 logx = y
(logx)^2-log(x^2)-3=0
(logx)^2-2logx -3=0
(log x -3)(log x + 1) = 0
log x = 3 or log x = -1(捨去)

2007-12-18 19:47:59 補充:
小提示:


no log x = -1 不等於 1/10
所有log (負數) 都是無定義的,
所以見到這個情況,立即可以捨去負數答案。


by chak11928
2007-12-17 3:25 am
可能答案是 =13


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