The second derivative
[src]

2*cosh(x) --------- 3 sinh (x)

$$\frac{2 \cosh{\left(x \right)}}{\sinh^{3}{\left(x \right)}}$$

The third derivative
[src]

/ 2 \ | 3*cosh (x)| 2*|1 - ----------| | 2 | \ sinh (x) / ------------------ 2 sinh (x)

$$\frac{2 \left(1 - \frac{3 \cosh^{2}{\left(x \right)}}{\sinh^{2}{\left(x \right)}}\right)}{\sinh^{2}{\left(x \right)}}$$

The graph