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If S(n) the sum of first n terms of an A...

If `S_(n)` the sum of first n terms of an A.P. is given by `Sn = 3n^(2) - 4n`, find the nth term.

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To find the nth term of the arithmetic progression (A.P.) given that the sum of the first n terms \( S_n \) is given by the formula \( S_n = 3n^2 - 4n \), we can follow these steps: ### Step 1: Find the first term \( a_1 \) The first term of the A.P. can be found by substituting \( n = 1 \) into the sum formula \( S_n \). \[ S_1 = 3(1)^2 - 4(1) = 3 - 4 = -1 \] Thus, \( a_1 = S_1 = -1 \). ### Step 2: Find the second term \( a_2 \) The second term can be found by substituting \( n = 2 \) into the sum formula \( S_n \). \[ S_2 = 3(2)^2 - 4(2) = 3(4) - 8 = 12 - 8 = 4 \] Now, since \( S_2 = a_1 + a_2 \), we can find \( a_2 \): \[ S_2 = a_1 + a_2 \implies 4 = -1 + a_2 \implies a_2 = 4 + 1 = 5 \] ### Step 3: Find the common difference \( d \) The common difference \( d \) can be found by subtracting the first term from the second term: \[ d = a_2 - a_1 = 5 - (-1) = 5 + 1 = 6 \] ### Step 4: Write the formula for the nth term The formula for the nth term \( a_n \) of an A.P. is given by: \[ a_n = a_1 + (n - 1) \cdot d \] Substituting the values of \( a_1 \) and \( d \): \[ a_n = -1 + (n - 1) \cdot 6 \] ### Step 5: Simplify the expression Now, we simplify the expression: \[ a_n = -1 + 6(n - 1) = -1 + 6n - 6 = 6n - 7 \] ### Final Answer Thus, the nth term of the A.P. is: \[ \boxed{6n - 7} \] ---
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CBSE COMPLEMENTARY MATERIAL-ARITHMETIC PROGRESSION -SHORT ANSWER TYPE QUESTIONS-II
  1. Find the middle term(s) of the A.P. 7,\ 13 ,\ 19 ,\ ddot,\ 241 .

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  2. Find the sum of integers between 10 and 500 which are divisible by 7

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  3. The sum of 5th and 9th term of an A.P. is 72 and the sum of 7th and...

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  4. If the mth term of an A.P. be 1//n and nth term be 1//m then show that...

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  5. If the p^(t h) term of an A.P. is q and the q^(t h) term is p , prove ...

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  6. Find the number of natural numbers between 101 and 999 which are di...

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  7. The sum of 5th and 9th terms of an A.P. is 30. If its 25th term is thr...

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  8. If sn , the sum of first n terms of an A.P., is given by Sn=5n^2+3n , ...

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  9. Which term of the AP 3, 15, 27, 39,… will be 120 more than its 21st te...

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  10. If S(n) the sum of first n terms of an A.P. is given by Sn = 3n^(2) ...

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  11. In a flower bed, there are 23 rose plants in the first row, 21 in the ...

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  12. For what value of n, are the with terms of two APs: 63, 65, 67, . . . ...

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  13. Which term of the A.P. 3,\ 15 ,\ 27 ,\ 39 ,\ will be 132 more t...

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  14. If the sum of the first 14 terms of an AP is 1050 and its first term ...

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  15. Find the sum of the odd numbers between 0 and 50.

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  16. If Sn = 4n^(2) - n^(2) in an A.P. find the A.P.

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  17. How many terms of the AP: 9, 17, 25, . . . must be taken to give a sum...

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