We all know the series expansion $$\log 2=\sum_{n=1}^{\infty}\frac{(-1)^{n-1}}n. \tag1$$ I also am able to use the method of [Wilf-Zeilberger][1] to the effect that $$\log 2=3\sum_{n=1}^{\infty}\frac{(-1)^{n-1}}{n\binom{2n}n2^n}. \tag2$$ >**QUESTION.** Can you provide yet another proof of the formula in (2)? **Remark.** My motivation for this question goes beyond this particular series, hoping it paves a way forward in my study. **Postscript.** After those generous replies (see below), it appears that the idea rests on $$\log\left(1+\frac1x\right)=2\sinh^{-1}\left(\frac1{2\sqrt{x+x^2}}\right)$$ so that we may put $x=1$ to obtain (1) and (2). To reveal the background: (2) is found from (1) by a "series acceleration" method which does not even stop there. In fact, stare at this one $$\log 2=\sum_{n=1}^{\infty}\frac{42n-9}{n(2n-1)\binom{4n}{2n}2^{2n+1}}. \tag3$$ One may now ask: can you furnish an alternative proof for the formula in (3)? [1]: https://en.wikipedia.org/wiki/Wilf%E2%80%93Zeilberger_pair