Given the following two formulas for an arithmetic sequence, which of the statements below are true?

Check all that apply.

The explicit formula:

an = a1 + (n - 1) • d

The recursive formula:

an = an-1 + d.

A. a1 is the previous term in the sequence
B. a1 is the first term in the sequence
C. an-1 is the nth term in the sequence
D. n is the index of the sequence
E. an is the previous term in the sequence