If 2^x = 5^y = 10^z, then
A. z = xy
B. z = x + y
C. z = (x+y)/(xy)
D. z = (xy)/(x+y)
step + ans
Logarithmic Question
2007-11-12 1:41 am
回答 (3)
2007-11-12 1:47 am
✔ 最佳答案
2x= 5y = 10zxlog2 = ylog5 = z
x = z/log2
y = z/log5
1/x+1/y
=(1/z)(log2+log5)
=1/z
1/z= (x+y)/xy
z = xy/(x+y)
Therefore,the answer is D
2007-11-16 9:30 pm
選得好!!! copy cat 的回答不可以做最佳ge !!!
2007-11-12 1:54 am
2^x = 5^y = 10^z
x log2 = y log5 = z(log2 + log5)
x log2 = y log5
x/y = log5/log2
y log5 = z(log2 + log5)
z/(y-z) = log5/log2
x/y = z/(y-z)
xy-xz = yz
z(y+x) = xy
z = xy/(x+y)
The answer is D.
x log2 = y log5 = z(log2 + log5)
x log2 = y log5
x/y = log5/log2
y log5 = z(log2 + log5)
z/(y-z) = log5/log2
x/y = z/(y-z)
xy-xz = yz
z(y+x) = xy
z = xy/(x+y)
The answer is D.
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https://hk.answers.yahoo.com/question/index?qid=20071111000051KK03376