Sum to n terms of the series `1/(5!)+1/(6!)+(2!)/(7!)+(3!)/(8!)+......` is

Sum to n terms the series 1+3+7+15+31+...

Sum up to n terms the series (3)/(2)-(5)/(6) +(7)/(18)...

Sum up to n terms the series 1-(2)/(5)+(3)/(5^(2))-(4)/(5^(3)) + ...

Find the nth term sum of n terms and sum to infinity terms of the series (1)/(2.5)+(1)/(5.8)+ (1)/(8.11)+ ...

Sum up to n terms of series (1)/(2)+(3)/(6)+(5)/(18) + ...

Sum to n terms of the series 1^(3) - (1.5)^(3) +2^(3)-(2.5)^(3) +…. is

Sum of n terms of the series (1^(4))/(1.3)+(2^(4))/(3.5)+(3^(4))/(5.7)+…. is equal to

Sum of n terms of the series 1/(1.2.3.4.)+1/(2.3.4.5) +1/(3.4.5.6)+....

Sum of n terms of the series 1/(1.2.3.4.)+1/(2.3.4.5) +1/(3.4.5.6)+....

If the sum of n term of the series (5)/(1.2.3) + (6)/(2.3.4) + ( 7)/(3.4.5)+"…." is a/2 - (n+b)/((n+1)(n+2)) , then