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

1 Answer
Gió
Sep 11, 2015

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

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