qqp question1: What is the value of [math] \displaystyle \sum_{n=1}^{\infty }{\frac{{{\left( -1 \right)}^{n+1}}}{4{{n}^{2}}-1}} [/math] ? question2: What is the value of [math]\sum_ {n=1} ^ {\infty} n^ {-n}[/math]?