If #log_3 5 = x#, what is #x#?

1 Answer
Mar 6, 2016

#x = log_3 (5) = log(5)/log(3) ~~ 1.465#

Explanation:

#x# is the Real solution to #3^x = 5#

We can use the change of base formula:

#log_a b = (log_c b) / (log_c a)#

with #a=3#, #b=5# and #c = 10# or #c = e# to allow the calculation of an approximation for #log_3 5# in terms of common or natural logarithms.

Using common (base #10#) logarithms:

#log_3 5 = (log_10 5) / (log_10 3) ~~ 0.69897 / 0.47712 ~~ 1.465#