Question

How do you evaluate `log_3 7` using the change of base formula?

Answer 1

I found: `1.77124`

Explanation:

The change of base allows you to change from a base, say `b`, to a new base `c` as:
`log_b(x)=(log_c(x))/(log_c(b))`
Where the new base `c` can be choosen to be "easy" to evaluate; if you have a pocket calculator, the new base could be `e` that can be evaluated using the Natural Logarithm (`ln`) on the calculator.
We write:
`log_3(7)=(log_e(7))/(log_e(3))=(ln(7))/(ln(3))=1.77124`