My Math Forum (http://mymathforum.com/math-forums.php)
-   Algebra (http://mymathforum.com/algebra/)
-   -   Logarithms (http://mymathforum.com/algebra/13279-logarithms.html)

 adhiluhur June 12th, 2010 09:59 PM

Logarithms

http://img295.imageshack.us/img295/3272/snapshot9.png
According to the book, the answer is "2"
Can anyone prove it?

 Phatossi June 13th, 2010 03:00 AM

Re: Logarithms

$\log_3 36-4\log_9 30 +16\log_{81} \sqrt15=$

$\log_3 3^2 +\log_3 4 - 2 \log_3 30+ 4\log_3 15^{1/2}=$

$2+\log_3 4 -2\log_3 15*2 + 2\log_3 15=$

$2+\log_3 4-2\log_3 15 - 2\log_3 2 + 2\log_3 15=$

$2+2\log_3 2 - 2\log_3 2=2$

I just did the maths actions without explaining, considering that you will know the steps that this exercise is going and if you don't understand anything feel free to ask. At the first line there is $\log \sqrt15$ with base 81 and not 8 like it is being showed. I tried to fix it but I couldn't. So I hope this will help.

 All times are GMT -8. The time now is 12:45 PM.