$\displaystyle \lim _ {x \rightarrow \pi /3} {\left (\frac{x} {x-} \pi /3 \int _ {\pi /3} ^ {x} {\cos \frac{t} {t} dt} \right)}$ 의 값은?

• ①$\displaystyle \frac{1} {2}$
• ②$1$
• ③$\displaystyle \frac{3} {2}$
• ④$2$
• ⑤$\displaystyle \frac{5} {2}$