Instructions: Help please.
Given that log 4= 0.6021, log 9= 0.9542 and log 12= 1.0792, evaluate each logarithm.
Problem--- 20. log 0.00009

Question

Instructions: Help please. 
Given that log 4= 0.6021, log 9= 0.9542 and log 12= 1.0792, evaluate each logarithm. 
Problem--->  20. log 0.00009

tkhunny · Answer

$0.00009 = 9*10^{-5}$

anonymous · Answer

why is that ?

tkhunny · Answer

Definition

$9 = 9*10^{0}$
$0.9 = 9*10^{-1}$
$0.09 = 9*10^{-2}$
$0.009 = 9*10^{-3}$
$0.0009 = 9*10^{-4}$

It's just the way it works.

anonymous · Answer

wouldn't it be log 10^-5 + log 9 ?

anonymous · Answer

then -5 + 0.9542 <-- (log 9) = 5.9 ?

tkhunny · Answer

???  What happened to the negative sign on the 5?

anonymous · Answer

its still there... my bad i calculated wrong , answer ? --> -4.0458 ?

tkhunny · Answer

That's better.

anonymous · Answer

that would be the answer ?

tkhunny · Answer

You were expecting something else?  It looks good to me.

anonymous · Answer

no i just wanted to be reassured that, that was the correct answer.

tkhunny · Answer

There's a lot of that going around.  Keep doing things well and you will develop more confidence in your own work.