Find the summation of:
[math] \sum_{n=1}^{\infty} \frac{(-1)^{n-1}}{n} (1-\frac{1}{2}+\frac{1}{3}-...+\frac{(-1)^{n+1}}{n}) [/math]
We know this is an alternating harmonic series if we look at the first part is just [math] \sum_{n=1}^{\infty}\frac{(-1)^{n-1}}{n} [/math] and multiplied to the second part which is [math] \sum_{n=1}^{\infty}\frac{(-1)^{n+1}}{n} [/math], this is also another alternating harmonic series. So the product of these two should converge to ln(2) for each part right? But I don't know how to show how they converge... so the summation is just (ln(2))^2?
Or another way I looked at it is, distributing...
[math] \sum_{n=1}^{\infty} (1\frac{(-1)^{n-1}}{n}-\frac{1}{2}\frac{(-1)^{n-1}}{n}+\frac{1}{3}\frac{(-1)^{n-1}}{n}-...+\frac{(-1)^{n+1}}{n}\frac{(-1)^{n-1}}{n}) [/math]
and then we can compute each summation separately, but yet, I still cannot get anywhere with that....