Question

Find the 21st term in the arithmetic sequence. 3, 7, 11, 15, 19, ...

Answer 1

The 21st term of the given arithmetic sequence is 83. The nth term of an arithmetic sequence is applied to find the required value where n = 21.

What is the nth term of an arithmetic series?

The nth term of an arithmetic sequence is calculated by the formula

aₙ = a + (n - 1) · d

Here the first term is 'a' and the common difference is 'd'.

Calculation:

The given sequence is an arithmetic sequence.

3, 7, 11, 15, 19, ....

So, the first term in the sequence is a = 3 and the common difference between the terms of the given sequence is d = 7 - 3 = 4.

Thus, the required 21st term in the sequence is

a₂₁ = 3 + (21 - 1) × 4

⇒ a₂₁ = 3 + 20 × 4

⇒ a₂₁  = 3 + 80

∴ a₂₁  = 83

So, the 21st term in the given arithmetic sequence is 83.

Learn more about the arithmetic sequence here:

brainly.com/question/6561461

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