a) log1/45
更新1:
Solve the following equations b)49^x-2=32
Math; log
2011-04-10 7:43 pm
Given that log2=a,log3=b,express each of the following in term of a and b
a) log1/45
a) log1/45
回答 (2)
2011-04-10 7:47 pm
✔ 最佳答案
a)log (1/45)= log 1 - log 45= - log 45= - log (3² x 10 / 2)= - (2 log 3 + log 10 - log 2)= - (2b + 1 - a)= a - 2b - 12011-04-10 11:49:53 補充：
Alternatively :
log (1/45)
= log (2/90)
= log 2 - log 90
= log 2 - log (3² x 10)
= log 2 - 2log3 - log10
= a - 2b - 1
2011-04-10 15:32:33 補充：
49^(x－2)=32
Sol
49^(x－2)=32
(x－2)log49=log32
2(x－2)log7=5log2
X－2=5log2/(2log7)
x=2+5log2/(2log7)
2011-04-15 4:54 am
a)log1/45
=log1-log45
=0-log(90/2)
= -log(2x5x3x3) - log2
= -(log2+log5+log3+log3) - log2
= - log2-log3-log3-log5-log2
= -2a-2b-log(10/2)
=-2a-2b-(1-log2)
= -a-2b-1
b)49^x-2=32
49^x =30
2011-04-14 20:58:54 補充：
49^x-2=32
49^x=30
x=log30/log49
x=log30/(2log7)
=log1-log45
=0-log(90/2)
= -log(2x5x3x3) - log2
= -(log2+log5+log3+log3) - log2
= - log2-log3-log3-log5-log2
= -2a-2b-log(10/2)
=-2a-2b-(1-log2)
= -a-2b-1
b)49^x-2=32
49^x =30
2011-04-14 20:58:54 補充：
49^x-2=32
49^x=30
x=log30/log49
x=log30/(2log7)
參考: me
收錄日期: 2021-04-21 22:20:32
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