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