Find the sum of the series `2xx5 +5xx8+8xx11+……`to n terms.

Find the sum of the series – 1 + 5 + 11 +….to n terms.

Find the sum of the series : 11 + 103 + 1005 +.... to n terms.

Find the 20th term of the series 2xx4 + 4xx6 + 6xx8 +...+n terms.

If the sum of the series 2,5,8,11...is 60100 then find the value of n.

Find the sum of the following series : 2^2+5^2+8^2 +.... to 15 terms .

Find the sum of first n terms and the sum of first 5 terms of the geometric series : 1+2/3+4/9 + .........

Find the sum of the following series : 5.6+6.7+7.8 + .... to 25 terms .

Find the sum to n terms of the series given below:- 1xx2 + 2xx3 + 3xx4 + 4xx5 +...