Question

The sum of the first night term of an AP is n^2-3n. write down the 10th term
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Answer 1

T10 = 16

Explanation:

Using the expression for calculating the sum of an AP as:

Tn = Sn - Sn-1

When n = 10

T10 = S10 - S9

Given that;

Sn = n²-3n

S10 = 10²-3(10)

S10 = 100 - 30

S10 = 70

S9 = 9² - 3(9)

S9 = 81 - 27

S9 = 54

Substitute the given values

T10 = S10 - S9

T10 = 70 - 54

T10 = 16

Hence the 10th term of the sequence is 16