Write an explicit formula for the n^th term a n 13, 17, 21, 25, ...

The first term in our arithmetic sequence = 13

The common difference of our arithmetic sequence = 17 - 13 = 4

The formula for finding an equation for any arithmetic sequence is a(n) = A + B(n - 1)

A = the first term

B = the common difference.

Let's plug our numbers in.

a(n) = 13 + 4(n - 1)

Let's check to make sure we're correct.

a(1) = 13 + 4(1 - 1) = 13 + 4(0) = 13 + 0 = 13

a(2) = 13 + 4(2 - 1) = 13 + 4(1) = 13 + 4 = 17

That verifies that our formula is correct.

In conclusion,

a(n) = 13 + 4(n - 1)

20

step-by-step explanation: