# logarithmic question

• November 22nd 2010, 11:20 PM
patci
logarithmic question
I need help with some examples :

a) 100 ^1+log5
b) 8^log2(5 - 1/3)

what kinds of formulas should I use?

In the first example I'm thinking about changing 1 to log5 (5), but I don't know if it has any sense
• November 22nd 2010, 11:31 PM
emakarov
Quote:

a) 100 ^1+log5
Do you mean $100^1+\log 5$ or $100^{1+\log 5}$, and log to what base?

Quote:

b) 8^log2(5 - 1/3)
Rewrite 8 as 2^3 and use $(a^b)^c=a^{bc}$ and $2^{\log_2x}=x$.
• November 23rd 2010, 06:59 AM
patci
Quote:

Originally Posted by emakarov
or $100^{1+\log 5}$

I meant this one. Exactly, index of the power amount to 1 + log5
• November 23rd 2010, 07:05 AM
Plato
Assuming you mean $\log_{10}(5)$ then $\displaystyle 10^{\log(5)}=5$.