Question

Find an explicit formula for the arithmetic sequence
-45, -30, -15, 0, ....

Answer 1

an = -45 +15(n -1)

Explanation:

The explicit formula for an arithmetic sequence is ...

an = a1 +d(n -1)

where an is the n-th term; a1 is the first term (-45), and d is the common difference (15). Filling in the values for the given sequence, we find the formula to be ...

an = -45 +15(n -1)