How do you use the Change of Base Formula and a calculator to evaluate the logarithm #log_(1/2) 15#?

1 Answer
Sep 11, 2015

Answer:

I found: #-3.9#

Explanation:

The Change of Base Formula tells you that:
#log_ab=log_cb/log_ca# so that basically you changed the old base #a# into the new one #c#.
In our case we can choose, as new base, the number #e# that gives us the natural log, #ln#, that it is possible to find with a pocket calculator. So:
#log(1/2)15=ln15/ln(1/2)=-3.9#