Solutions - 0140-04

(a) ${\displaystyle \sum _{n=1}^{\infty }{(-1)}^{n-1}\frac{1}{n^3}}$

(b) ${\displaystyle \sum _{n=1}^{\infty }\frac{n+1}{n+5}}$

(c) ${\displaystyle \sum _{n=1}^{\infty }{(-1)}^{n-1}\frac{n+2}{5^n}}$