/log(1 + (1 + x)*(-1 + x)) / / ___ \ / ___ \\
|------------------------- for Or\And\x <= \/ 2 , x > 0/, And\x >= -\/ 2 , x < 0//
| (1 + x)*(-1 + x)
|
| oo
| ____
| \ `
< \ n
| \ / 2\
| ) \1 - x / otherwise
| / ---------
| / 1 + n
| /___,
| n = 0
\
$$\begin{cases} \frac{\log{\left(\left(x - 1\right) \left(x + 1\right) + 1 \right)}}{\left(x - 1\right) \left(x + 1\right)} & \text{for}\: \left(x \leq \sqrt{2} \wedge x > 0\right) \vee \left(x \geq - \sqrt{2} \wedge x < 0\right) \\\sum_{n=0}^{\infty} \frac{\left(1 - x^{2}\right)^{n}}{n + 1} & \text{otherwise} \end{cases}$$
Piecewise((log(1 + (1 + x)*(-1 + x))/((1 + x)*(-1 + x)), ((x > 0)∧(x <= sqrt(2)))∨((x < 0)∧(x >= -sqrt(2)))), (Sum((1 - x^2)^n/(1 + n), (n, 0, oo)), True))