# Logarithm help

• April 11th 2011, 08:11 PM
BuhRock
Logarithm help
I don't understand how you can get -2 out of log base 2 1/4 ?
• April 11th 2011, 08:26 PM
pickslides
$\log_2 \frac{1}{4} = \log_2 \frac{1}{2^2} = \log_2 2^{-2}= -2 \times \log_2 2 = -2 \times 1$
• April 11th 2011, 09:06 PM
johnny
• April 12th 2011, 04:25 AM
DrSteve
Here's another way:

$\log_2 \frac{1}{4}=x$ is equivalent to $2^x=\frac{1}{4}=2^{-2}$.

So $x=-2$.