Question 24
Find the value of
$$
\sum_{a=1}^{\infty} \sum_{b=1}^{\infty} \sum_{c=1}^{\infty} \frac{a b(3 a+c)}{4^{a+b+c}(a+b)(b+c)(c+a)}
$$
$$
\sum_{a=1}^{\infty} \sum_{b=1}^{\infty} \sum_{c=1}^{\infty} \frac{a b(3 a+c)}{4^{a+b+c}(a+b)(b+c)(c+a)}
$$
MathNet 2019-part-08 — 179 problems (EN–VI) Question 24
Math Olympiad Vault · MathNet 2019-part-08 — 179 problems (EN–VI)