Question

How do you find the formula for `a_n` for the arithmetic sequence `a_1=15, d=4`?

Answer 1

Look at the first few terms and discover a pattern.

Explanation:

Look at the first few terms:

`a_1 = 15 = 15+ 4(0)`

`a_2= 19= 15+4(1)`

`a_3= 23 = 15 + 4(2)`

Please observe that:

`a_n = a_1+d(n-1)`