要解釋 PLEASE SHOW STEPS (共3題)
第一題:
If log x^2 + log y^2 = log z^2 , where x, y and z are positive numbers, which of the following is/are true ?
(1) x ^2 + y^2 = z^2
(2) log x + logy = logz
(3) x^2 y^2 = z^2
第2題:
If 5^a = 2^b = 10^c and a,b,c are non- zero, then c/a +c/d = ???
第3題:
Suppose log 4 =b. Express log 32 in terms of b
F4 MATHS
2008-02-08 6:42 am
回答 (1)
2008-02-08 7:01 am
✔ 最佳答案
第一題logx^2+logy^2=logz^2
log(xy)^2=logz^2
全式消log
x^2y^2=z^2
logx^2+logy^2=logz^2
2logx+2logy=2logz
全式除2
logx+logy=logz
第二題
5^a=10^c
log5^a=log10^c
alog5=clog10 (log10=1)
c/a=log5
(唔知係c/d定c/b)
if c/b
2^b=10^c
blog2=clog10
c/b=log2
第三題
log32
=log4*4*2
=log4+log4+log2
=b+b+1/2log4
=b+b+1/2b
=2.5b
參考: myself
收錄日期: 2021-04-23 22:58:02
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20080207000051KK02300