Question

Can someone check this for me..

For the following arithmetical sequence, determine a1 and d1 and find an explicit formula for the sequence: -8, -5, -2, 1.

What is a1? a=-3

What is the common difference d?
Write an explicit formula for an using the formula for the arithmetical sequences an=a1+(n-1)d.

Answer 1

d = 1 - (-2) = 3

Answer 2

Ah, I see. Thank you

Answer 3

a1, is the first term of the sequence.
d is the generally reffered to the common difference.
it can be observed, that if 3 is added to each term, the next term is obtained.
thus, d=3. a=-8.