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If the sum of first n terms of an A.P. i...

If the sum of first n terms of an A.P. is `2n^(2) - n + 1`, then the tenth term of this A.P. is :

A

36

B

37

C

38

D

39

Text Solution

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The correct Answer is:
To find the tenth term of the arithmetic progression (A.P.) given that the sum of the first n terms is \( S_n = 2n^2 - n + 1 \), we will follow these steps: ### Step 1: Find the nth term of the A.P. The nth term \( a_n \) of an A.P. can be calculated using the formula: \[ a_n = S_n - S_{n-1} \] where \( S_n \) is the sum of the first n terms and \( S_{n-1} \) is the sum of the first \( n-1 \) terms. ### Step 2: Calculate \( S_{n-1} \) To find \( S_{n-1} \), we substitute \( n-1 \) into the sum formula: \[ S_{n-1} = 2(n-1)^2 - (n-1) + 1 \] Expanding this: \[ S_{n-1} = 2(n^2 - 2n + 1) - (n - 1) + 1 \] \[ = 2n^2 - 4n + 2 - n + 1 + 1 \] \[ = 2n^2 - 5n + 4 \] ### Step 3: Calculate \( a_n \) Now we can find \( a_n \): \[ a_n = S_n - S_{n-1} \] Substituting the values we have: \[ a_n = (2n^2 - n + 1) - (2n^2 - 5n + 4) \] \[ = 2n^2 - n + 1 - 2n^2 + 5n - 4 \] \[ = 4n - 3 \] ### Step 4: Find the 10th term \( a_{10} \) Now we substitute \( n = 10 \) into the formula for \( a_n \): \[ a_{10} = 4(10) - 3 \] \[ = 40 - 3 \] \[ = 37 \] ### Conclusion The tenth term of the A.P. is \( \boxed{37} \). ---

To find the tenth term of the arithmetic progression (A.P.) given that the sum of the first n terms is \( S_n = 2n^2 - n + 1 \), we will follow these steps: ### Step 1: Find the nth term of the A.P. The nth term \( a_n \) of an A.P. can be calculated using the formula: \[ a_n = S_n - S_{n-1} \] where \( S_n \) is the sum of the first n terms and \( S_{n-1} \) is the sum of the first \( n-1 \) terms. ...
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