The sum of first n terms of an arithmetic sequence is `n^2+2n` Find the common difference.

The sum of first n terms of an arithmetic sequence is n^2+2n What is the first term?

The sum of first n terms of an arithmetic sequence is n^2+2n What is the sum of first 20 terms of this sequence?

Sum of first n terms of an arithmetic sequence is 8n^2 +5n. Find the sum of first 20 terms.

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?

What is the sum of first 40 natural numbers? [(1640 , 820 , 410 , 205)] ii) Whât is the sum of first 40 terms of the arithmetic sequences 6,12,18,.....? iii) The sum of first 40 terms of an arithmetic sequence with common difference 6 , is '5120 .' Write down the aigebraic form of this sequence.

The sum of first n terms of an arithmetic sequence is n^2+2n Prove that the sum of continuous terms starting from the first of the sequence 3,5,7,..... added to 1 gives a perfect square.

The second term of an arithmetic sequence is 8 and the common difference is 3. Write the sequence?

The algebraic form for the sum of first n terms of an arithmetic sequence is 2n^(2) +8n'. How many consecutive terms of the sequence, starting from the first, are to be added to get 330 ?

The sum of first 9 terms of an arithmetic sequence is 45 and the sum of first 18 terms is 171. Find the sum of 5^(th) to 14^(th) terms.

The sum of first 9 terms of an arithmetic sequence is 45 and the sum of first 18 terms is 171. Find its 14^(th) term.