" The sum of the infinite series `1+(2)/(3)+(7)/(3^(2))+(12)/(3^(3))+(17)/(3^(4))+(22)/(3^(3))+....` is equal to:

The sum of the series (1)/(3)+(1)/(3^(2)xx2)+(1)/(3^(3)xx3)+(1)/(3^(4)xx4)+... is :

The sum of the infinite series (5)/(17)+(55)/((17)^(2))+(555)/((17)^(3))+….. is

The sum of the infinite series,1^(2)-(2^(2))/(5)+(3^(2))/(5^(2))-(4^(2))/(5^(3))+(5^(2))/(5^(4))......is

The sum of infinite series (1)/(10)+(2)/(10^(2))+(3)/(10^(3))+...+(n)/((10)^(n)) is

The sum of the series 1+ 2/3+ (1)/(3 ^(2)) + (2 )/(3 ^(3)) + (1)/(3 ^(4)) + (2)/(3 ^(5)) + (1)/(3 ^(6))+ (2)/(3 ^(7))+ …… upto infinite terms is equal to :

Find the sum of the infinite series (1.3)/(2)+(3.5)/(2^(2))+(5.7)/(2^(3))+(7.9)/(2^(4))+......oo