If `S_(n) = 1 + 3 + 7 + 13 + 21 + "….."` upto n terms, then

Find 1 xx 5 + 3 xx 7 + 5 xx 9 + 7 xx 11 .... upto n terms.

If (1 xx 2 + 2 xx 3 + 3 xx 4 + 4 xx 5+ … upto n terms) / (1 + 2 + 3 + 4 + ………………….. upto n terms) = 100 / 3 , find n

Find S_n , if S_n = 1.3 + 2.4 + 3.5 + … upto n terms.

Find the sum of the series 3 + 7 + 13 + 21 + 31 + … to n terms . Find the sun when n=20

Find the sum of the series 3 + 7 + 13 + 21 + 31 + … to n terms . Find the sun when n=20

2.4 + 4.7 + 6.10+ …. upto (n-1) terms=

If S_1 = 3, 7, 11 15, … upto 125 terms and S_2 = 4, 7, 10, 13, 16, … upto 125 terms the how many terms are there in S_1 that are there in S_2 ?

Find 3.7 + 5.10 + 7.13 + 9.16 + … upto 'n' term.

(1-1/n) + (1 - 2/n) + (1 - 3/n)+ …… upto n terms = ?

Find the sum of 1^1 n + 2^2 (n - 1) + 3^2 (n - 2) + 4^2 (n -3) ……upto 'n' terms.