Question

How do you use the Change of Base Formula and a calculator to evaluate `log_2 8`?

Answer 1

You should get `3`:

Explanation:

Actually using the definition of log you get:
`log_2(8)=x`
`2^x=8`
`2^x=2^3`
`x=3`
or:

The Change of Base Formula tells you that:
`log_ab=log_cb/log_ca` where `a` is the old and `c` is the new base.
We can choose `c=10` that gives you a log that can easily be evaluated using a pocket calculator getting:
`log_2(8)=log_10(8)/log_10(2)=3`