[" 21.Find the "n" th term and sum to "],[" (i) "2+6+12+20+...]

Find the nth term and sum to n tems of the following series: 2+6+12+20+…

Find the nth term and sum to n tems of the following series: 2+6+12+20+…

(i) The sum of the first n terms of an AP is ((5n^(2))/(2) + (3n)/(2)) . Find the nth term and the 20th term of this AP. (ii) The sum of the first n terms of an AP is ((3n^(2))/(2) + (5n)/(2)). Find its nth term and the 25th term.

Find the n th term and the sum of first n terms of thefollowing sequence 2,7,20,57,166,..

Find the sum to n terms of series 2+6+12+20+.........

Find the 20^(th) term and n^(th) term of the G.P. 4,12,36…. .

Find (i) the n^(th) term and (ii) the sum of first n terms of the series 6+15x+28x^(2)+45x^(3)+...

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

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

Find the n^(th) term and 12^(th) term of the sequence 6, 18, 54 ……