How do you use the Change of Base Formula and a calculator to evaluate the logarithm log_3 73?

1 Answer
Daniel L.
Jul 9, 2015

log_3 73~~3.095

Explanation:

The Change of Base Formula says that:

log_a x=log_b x/log_b a

Calculators don't have log_3 x button, but they have "log" which is base 10 logarythm and "ln" which is natural logarythm (base e), so you can use this formula in such a way (using base 10 log):

1) Calculate log 3
2) Put the result in memory (button "X->M" or simmilar)
3) Calculate log 73
4) Press divide button
5) Recall memory result (button "RM" or simmilar)
6) Press result (=) button.

Note: Using "ln" instead of "log" is also possible.

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