How do you use the Change of Base Formula and a calculator to evaluate the logarithm #log 4^20#?
There is a good possibility that the intended question is to find
In any case the change of base formula says (in its general form) that
For a, b, x positive,
#log_b x = log_a x/(log_a b)#
Because calculators tend to have built-in functions for base 10 logs,
For b, x positive,
#log_b x = log x/(log b)" "#or #" "log_b x = ln x/(ln b)#
The sequence of button to press depends on the calculator you are using.
On the calculator that is included in windows (scientific view)
press: 20 "ln" / 4 "ln" =