Question

Which logarithmic function can be used to approximate the value of y in the equation 4^y=5?

Answer 1

From the definition of logarithm, we know that:


`$a^y=b\quad\iff\quad y=\log_ab\qquad\quad \,\text{when }a,b\ \textgreater \ 0\,\,\text{ and }\,\,a\\eq1`

In this case
`a=4` and
`b=5` so:


`$\boxed{y=\log_45}`