Question

Write the explicit formula for the arithmetic sequence. 2, -2, -6, -10, -14, ... A) an = 5 - 3n B) an = 6 - 4n C) an = 8 - 6n D) an = 10 - 8n

Answer 1

B

Explanation:

The n th term (explicit formula) of an arithmetic sequence is

`a_(n)` = a₁ + (n - 1)d

where a₁ is the first term and d the common difference

Here a₁ = 2 and d = - 2 - 2 = - 4, thus

`a_(n)` = 2 - 4(n - 1) = 2 - 4n + 4 = 6 - 4n → B