Question

The explicit formula for a sequence is

an= −2 + 3/2 (n − 1)

What is the 21st term of the sequence?

Answer 1

28

Explanation:

Let n = 21, and evaluate the expression.

`a_n = -2 + (3)/(2)(n - 1)`

`a_(21) = -2 + (3)/(2)(21 - 1)`

`a_(21) = -2 + (3)/(2)(20)`

`a_(21) = -2 + (3)/(1)(10)`

`a_(21) = -2 + 30`

`a_(21) = 28`