Sum of n Terms of an A.P. | Examples

Sum of first terms of an A.P. is 9 less than the sum of next 3 terms of the same A.P. and second term is 2 then 4^(th) term of that A.P. is :

If the sum of m terms of an A.P. is same as the sum of its n terms, then the sum of its (m+n) terms is

The sum of 8 terms of an A.P. is -64 and sum of 17 terms is 289. Find the sum of its 'n' terms.

If the sum of p terms of an A.P. is q and the sum of q terms is p , then the sum of the p+q terms will be

The sum of n terms of an A.P. is n^(2) + 3n . Find its 20th term.

Find the sum of n terms of an A.P. whose nth term is (2n+1).

The sum of m and n terms of an A.P. are n and m respectively. Prove that the sum of (m + n) terms will be - (m+n).