Find the sum of the first n-terms of the series. `2+22+222+…..`

Find the sum of the first n terms of the series whose nth term is n(n+3) .

Find the sum of the first n terms of the series : 3+7+13+21+31+. . .

Find the sum of n terms of the series 7+77+777+..

Using progression, find the sum of first five terms of the series 1+2/3+4/9+…..

Find the sum of the 1^(st) n terms of the series 3+7+13+21+31+ …

The first term of an arithmetic sequence is 2 and the common difference is 4 . a) Find the sum of the first ten terms of this sequence. b) Find the sum of ten terms from the second term to the eleventh term. .c) Is it possible that the sum of any consecutive ten terms of the sequence is 500 why?

Find the sum to n terms of the series, 2^2+ 5^2+8^2+……..

Find the sum of the first n terms of the arithmetic sequence 1/n,3/n,5/n,7/n ,.......

Let A, be the sum of the first n terms of the geometric series 704 + (704)/(2) +(704)/(4) +(704)/(8)+ cdots and B_(n) , be the sum of the first n terms of the geometric series 1984 - (1984)/(2) + (1984)/(4) -(1984)/(8) + cdots If A_(n), =B_(n) , then the value of n is (where n in N).