1.100^(log 9) *100^(log √3)
答:243
2.100^(log√8) / 100^(log16)
答:1/32
3.a)evaluate (√7+45^(1/2)-(√7-45^(1/2))^2
答:10
b)hence find the value of log (√7+45^(1/2)-(√7-45^(1/2))
答:1/2
4.if a^(-2x)+6=15,find the value of 12a^x
答:4
簡單maths
2007-10-27 10:11 pm
回答 (1)
2007-10-27 11:34 pm
✔ 最佳答案
1.Let a=log9 and b=log√3
then 10^a=9 and 10^b=√3
(10^a)^2=81 and (10^b)^2=3
10^(2a)=81 and 10^(2b)=3
(10^2)^a=81 and (10^2)^b=3
100^a=81 and 100^b=3
100^(log 9) *100^(log √3)
=(100^a)*(100^b)
=81*3
=243
2.
Let a=log√8 and b=log16
then 10^a=√8 and 10^b=16
Similar to Q1,
100^a=8 and 100^b=256
100^(log√8) / 100^(log16)
=8/256
=1/32
3.呢兩條怪怪哋, 因為每題有4個開括,3個關括.
4.
a^(-2x)+6=15
a^(-2x)=9
[a^(-2x)]^(-1/2)=9^(-1/2)
a^x=1/3
12a^x=4
收錄日期: 2021-04-13 14:12:01
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20071027000051KK02190