2.10.101 Number Series

Condition: a) Find out whether a positive series converges or disperses. b) Find out whether the alternate row converges or diverges, if the row converges, establish the nature of the convergence. a) \ (\ sum_ {n = 1}^{\ infty} \ arcsin \ left (\ frac {3} {4} \ right)^{n} \), b) \ (\ sum_ {n = 1}^{\ infty} \ frac {(-1)^{n} (5 n-2)} {n \ sqrt {25 n^{2} +1}} \).