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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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  • If the sum of n terms of an AP is given by S_n=n(2n-9) , then 10th term is

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