Find the indicated midpoint rule approximation to the following integral.

${\displaystyle \underset{1}{\overset{3}{}}}sin(\frac{}{3}x)dx$ using $n=6$ subintervals

${\displaystyle \underset{1}{\overset{3}{}}}sin(\frac{}{3}x)dx$~~

$($Round to four decimal places as needed.$)$