/ / / x\\
| | 18*log|1 + -||
| |6 \ 3/|
|-x*|- - -------------|
| |x 2 |
| \ x /
|----------------------- for And(x <= 3, x > -3)
| 6
|
< oo
| ____
| \ `
| \ n -n n
| \ (-1) *3 *x
| / ------------ otherwise
| / 1 + n
| /___,
| n = 1
\
$$\begin{cases} - \frac{x \left(\frac{6}{x} - \frac{18 \log{\left(\frac{x}{3} + 1 \right)}}{x^{2}}\right)}{6} & \text{for}\: x \leq 3 \wedge x > -3 \\\sum_{n=1}^{\infty} \frac{\left(-1\right)^{n} 3^{- n} x^{n}}{n + 1} & \text{otherwise} \end{cases}$$
Piecewise((-x*(6/x - 18*log(1 + x/3)/x^2)/6, (x <= 3)∧(x > -3)), (Sum((-1)^n*3^(-n)*x^n/(1 + n), (n, 1, oo)), True))