Sequences

Question 1

Arithmetic Sequence

Answer 1

The difference between two consecutive terms is always the same

an=a1+(n-1)d, where an is the nth term, a1 is the initial term, and d is the common difference.

To find the sum, use avg*nterms = sum
avg = (final + initial)/2

Question 2

Geometric Sequence

Answer 2

Every consecutive pair has the same ratio

an=a1(r)^(n-1), where an is the nth term, a1 is initial term, r is the commo ratio