Answer
$\displaystyle \frac{1}{2}\ln a$
Work Step by Step
Expressing the root with a rational exponent
$\sqrt{a}=a^{1/2}$
We get:
$\ln\sqrt{a}=\ln a^{1/2}$
Apply the rule:
$\log_{b}\left(x^{r}\right)=r\log_{b}x$
We get:
$=\displaystyle \frac{1}{2}\ln a$
