La Serie de arctan(x)

\sum_{n=1}^{∞ }{\frac{(-1)^{n+1}}{2n-1}x^{2n-1} }=arctanx

Si -1<x<1

k = 1 (slider from 1 to 100, step 1)
logaritmo = Sequence(((-1)^(n + 1) * x^((2 * n) - 1) / ((2 * n) - 1)), n, 1, k)
a = Sum(logaritmo)
f(x) = atan(x)
texto5: "\sum_{n=1}^{" + (LaTeX[k]) + "}{\frac{(-1)^{n+1}}{2n-1}x^{2n-1} }"