The sum to infinity of the series `1/2.4+1/4.6+1/6.8+1/8.10+.......` is

The sum to infinity of the series 1+(4)/(7)+(9)/(49)+(16)/(343)+.... is

If the sum to infinity of the series: 3+(3+d).1/4+(3+2d).1/(4^(2))+ ………. Is 4 8/9 find d. Also name the series.

The sum to infinity of the series 1+ (4)/(5) + (7)/(5^2) + (10)/(5^3) +....is

The sum to infinity of the series 1+(4)/(5)+(7)/(5^(2))+(10)/(5^(3))+ . . . , is