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the algebraic form of the sum of n terms of an arithmetic sequence is 3n2 + 5 n .what is the common difference ?​

1 Answer

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Answer:


d = 6

Explanation:

Given


S_n = 3n^2 + 5n

Required

Find d

First, find the sum of the first 1 term


S_1 = 3 * 1^2 + 5 * 1


S_1 = 8

The sum of the first 2 terms


S_2 = 3 * 2^2 + 5 * 2


S_2 = 22

Calculate the first term (a)


a = S_1


a = 8

Calculate the second term (T2)


T_2 = S_2 - S_1


T_2 = 22 - 8


T_2 = 14

The common difference is:


d = T_2 - a


d = 14 - 8


d = 6

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