$f \left (x \right) = \sinh ^ {-1} \left (2 \tan x \right)$ 의 $\displaystyle f ' \left (\frac{\pi} {3} \right)$ 는?

• ①$\displaystyle \frac{6} {\sqrt {13}}$
• ②$\displaystyle \frac{7} {\sqrt {13}}$
• ③$\displaystyle \frac{8} {\sqrt {13}}$
• ④$\displaystyle \frac{9} {\sqrt {13}}$
• ⑤$\displaystyle \frac{10} {\sqrt {13}}$