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

1 Answer
Gió
Oct 19, 2015

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

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