Sum to n terms the series : `2+5x + 8x^2+11x^3+........., |x| < 1`.

If the sum to infinity of the series 1 + 4x + 7x^2 + 10x^3 +............. is 35/16 then x= (A) 1/5 (B) 2/5 (C) 3/7 (D) 1/7

Find the sum to n terms of the following series : 1+2x+ 3x^2+4x^3+ .......... when |x|<1.

Find the sum to n terms of the following series : 1+ 3x+ 5x^2+7x^3+ .......... when |x|<1.

Find the sum to n terms of the following series : 1+4x+7x^2+10x^3 + .......... when |x|<1.

Sum to n terms the series : 1^2 - 2^2 + 3^2 - 4^2 + 5^2 - 6^2 + ...

Find the sum to n terms of the series : (x+1/x)^2+(x^2 + 1/x^2)^2+ (x^3 + 1/x^3)^2+ ...... .

Find the sum of n terms of the series 1. 2. 3+2. 3. 4+3. 4. 5+

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 to n terms of the following series : 1+3/2+5/2^2+7/2^3 + ...........

If the sum to 2n terms of the A.P. 2, 5, 8, 11, .... is equal to the sum to n terms of 57, 59, 61, 63, ....., then n=