log(3x-4)+log2 = 2logx
2) if log2=x ,log3=y ,express the following in term of x and y.
log√(50/81)
更新1:
3) solve the equation (logx)^2 =logx^2
Log. questions?
2016-10-03 9:28 am
1)solve the equation
log(3x-4)+log2 = 2logx
2) if log2=x ,log3=y ,express the following in term of x and y.
log√(50/81)
log(3x-4)+log2 = 2logx
2) if log2=x ,log3=y ,express the following in term of x and y.
log√(50/81)
回答 (2)
2016-10-03 9:36 am
✔ 最佳答案
1)log(3x - 4) + log(2) = 2 log(x)
log[2(3x - 4)] = log(x²)
2(3x - 4) = x²
x² = 6x - 8
x² - 6x + 8 = 0
(x - 2)(x - 4) = 0
x = 2 or x = 4
2)
log√(50/81)
= log[(50/81)^(1/2)]
= (1/2) log(50/81)
= (1/2) log[100/(2 × 81)
= (1/2) [log(100) - log(2 × 81)]
= (1/2) [log(10²) - log(2 × 3⁴)]
= (1/2) [2 log(10) - log(2) - log(3⁴)]
= (1/2) [2 × 1 - log(2) - 4 log(3)]
= (1/2) (2 - x - 4y)
2016-10-16 3:09 am
1
log(3x-4)+log2 = 2logx
log(3x-4)-log x^2=-log 2
log[(3x-4)/(x^2)]=log(1/2)
6x-8=x^2
x=4 or x=2
2.
log √(50/81)
=log(√50) -log 9
=0.5(log 5 +log 10)-2y
=0.5-2y+0.5 log(10/2)
=1+2y-0.5 log 2
=1+2y-0.5x
3)
(logx)^2 =logx^2
(logx)^2-2log x=0
(log x)(log x-1)=0
log x=1 or log x=0
x=10 or x=1
log(3x-4)+log2 = 2logx
log(3x-4)-log x^2=-log 2
log[(3x-4)/(x^2)]=log(1/2)
6x-8=x^2
x=4 or x=2
2.
log √(50/81)
=log(√50) -log 9
=0.5(log 5 +log 10)-2y
=0.5-2y+0.5 log(10/2)
=1+2y-0.5 log 2
=1+2y-0.5x
3)
(logx)^2 =logx^2
(logx)^2-2log x=0
(log x)(log x-1)=0
log x=1 or log x=0
x=10 or x=1
收錄日期: 2021-04-18 15:44:18
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20161003012807AANSwrB