/ / 2\ /x\ \
| \1 + x /*cosh|-| |
| 2*x \3/ /x\|
2*|- ---------- + ---------------- + coth|-||
| 2/x\ 3/x\ \3/|
| 3*sinh |-| 9*sinh |-| |
\ \3/ \3/ /
$$2 \left(- \frac{2 x}{3 \sinh^{2}{\left(\frac{x}{3} \right)}} + \frac{\left(x^{2} + 1\right) \cosh{\left(\frac{x}{3} \right)}}{9 \sinh^{3}{\left(\frac{x}{3} \right)}} + \coth{\left(\frac{x}{3} \right)}\right)$$
/ / 2/x\\ \
| | 3*cosh |-|| |
| / 2\ | \3/| |
| \1 + x /*|1 - ----------| |
| | 2/x\ | /x\|
| | sinh |-| | 2*x*cosh|-||
| \ \3/ / \3/|
2*|-1 + ------------------------- + -----------|
| 27 /x\ |
| 3*sinh|-| |
\ \3/ /
------------------------------------------------
2/x\
sinh |-|
\3/
$$\frac{2 \left(\frac{2 x \cosh{\left(\frac{x}{3} \right)}}{3 \sinh{\left(\frac{x}{3} \right)}} + \frac{\left(1 - \frac{3 \cosh^{2}{\left(\frac{x}{3} \right)}}{\sinh^{2}{\left(\frac{x}{3} \right)}}\right) \left(x^{2} + 1\right)}{27} - 1\right)}{\sinh^{2}{\left(\frac{x}{3} \right)}}$$