Sum the series upto n terms `1/2.5+1/5.8+1/8.11+....`

Find the sum of the series upto n terms 1.3.5+3.5.7+5.7.9+....

Sum the following series to n terms: 1/(1. 6)+1/(6. 11)+1/(11. 16)+1/(16. 21)++1/((5n-4)(5n+1))

1/2.5+1/5.8+1/8.11+….16 terms =

If n is a even number, find the sum of the series upto n terms 1^2-2^2+3^2-4^2+5^2-......

Find the sum of n terms of the series 1/2.5+1/5.8+1/8.11 …to n terms.

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 the following series to n terms: (1)/(1.6)+(1)/(6.11)+(1)/(11.16)+(1)/(16.21)+...+(1)/((5n-4)(5n+1))

Determine the sum of following series upto n terms. 1.3+5.7+9.11+ …….

Find the sum of the series upto n terms ((2n+1)/(2n-1))+3((2n+1)/(2n-1))^2+5((2n+1)/(2n-1))^3+.....