How do you use the Change of Base Formula and a calculator to evaluate the logarithm log_4 72?

1 Answer
Sep 24, 2015

I found: 3.0849

Explanation:

The Change of Base Formula allows you to write:

log_ab=(log_cb)/(log_ca)
and change your base from a to the new base c.

We can choose, as new base, e and use natural logs, ln, that can be evaluated using a pocket calculator and get:

log_4(72)=(ln72)/(ln4)=3.0849